By vs. Until – English Grammar Exercises for B2
Read the librarian’s strict instructions regarding the borrowing and returning of rare research materials carefully. Choose the best option to complete the sentences.
1 You must return the 18th-century manuscript to the front desk ______ Friday afternoon.
(a) until
(b) at
(c) by
(d) within
2 You are permitted to keep this restricted document in the reading room ______ 5:00 PM today.
(a) for
(b) by
(c) to
(d) until
3 The special collections archive will remain open ______ midnight for PhD students.
(a) until
(b) since
(c) by
(d) at
4 Please submit your formal renewal request ______ tomorrow morning if you need more time.
(a) until
(b) by
(c) in
(d) during
5 You have to wait in the lobby ______ the chief archivist arrives to unlock the vault.
(a) until
(b) by the time
(c) by
(d) as
6 If we do not receive the borrowed artifacts ______ the end of the month, you will be heavily fined.
(a) until
(b) in
(c) at
(d) by
7 You cannot take these fragile maps out of the designated viewing area ______ you sign the liability waiver.
(a) by
(b) until
(c) by the time
(d) to
8 The reservation for this book is valid ______ Monday, meaning you must collect it ______ then.
(a) until / by
(b) by / until
(c) until / until
(d) to / at
9 I will hold the first edition for you ______ 3 PM, but if you don’t arrive ______ that time, it goes to the next researcher.
(a) by / by
(b) until / by
(c) by / until
(d) until / at
10 Please do not leave the rare books desk ______ the librarian has checked the condition of all the pages.
(a) by
(b) during
(c) until
(d) by the time
11 All reference materials must be returned to their original shelves ______ 4:00 PM on the due date.
(a) until
(b) for
(c) by
(d) at
12 You may use the private study cubicle ______ the library officially closes.
(a) when
(b) until
(c) by
(d) to
13 Make sure to finish scanning the permitted pages ______ the archivist’s lunch break.
(a) during
(b) until
(c) in
(d) by
14 The special collection is entirely unavailable ______ next Tuesday because it is undergoing delicate restoration.
(a) by
(b) within
(c) until
(d) for
15 Not ______ the head preservationist gives her explicit approval will you be granted access to these medieval records.
(a) until
(b) by
(c) since
(d) when
16 To avoid a permanent suspension of your library privileges, all outstanding late fees must be cleared ______ the end of the current term.
(a) to
(b) by
(c) within
(d) until
17 The document will remain secured in the vault ______ such time as a formal request is approved; therefore, you must submit your forms ______ noon today.
(a) by / until
(b) until / at
(c) until / by
(d) to / before
18 The reading room will stay open ______ 10 PM, but the circulation desk closes earlier, meaning you must check out any books ______ 8 PM.
(a) until / until
(b) by / until
(c) to / in
(d) until / by
19 No researcher is permitted to photograph the artifacts ______ they have secured a special license, which must be acquired ______ the actual day of the visit.
(a) until / by
(b) by / until
(c) by the time / on
(d) unless / in
20 Should you fail to return the first-edition copy ______ the designated deadline, your borrowing rights will be revoked ______ further notice.
(a) until / by
(b) by / until
(c) at / to
(d) within / for
ANSWER KEY & EXPLANATIONS
1 (c) by
- Why it is correct (The Key): “Return” is a punctual action (it happens at a specific moment). “By” is used to show the deadline for an action to be completed.
- Error Analysis: (a) until (Common Mistake: You cannot continuously “return” a book over a period of time). (b) at (Meaning Trap: “At” means exactly at that second, but a deadline allows returning it before Friday afternoon too). (d) within (Structural Error: “Within” requires a duration, like “within 3 days”, not a specific day).
2 (d) until
- Why it is correct (The Key): “Keep” describes an ongoing state. “Until” is used to show how long a state or action continues before it stops.
- Error Analysis: (b) by (Common Mistake: “By” is for deadlines of completed actions, not ongoing states like keeping). (c) to (Structural Error: Usually used with “from… to…”, not alone for time limits here). (a) for (Structural Error: “For” requires a duration of time, e.g., “for 3 hours”).
3 (a) until
- Why it is correct (The Key): “Remain open” is an ongoing state. “Until” marks the end of that continuous state.
- Error Analysis: (c) by (Common Mistake). (b) since (Structural Error: “Since” marks the beginning of an action in perfect tenses, not the end). (d) at (Meaning Trap: “Open at midnight” means it starts opening then, reversing the library’s schedule).
4 (b) by
- Why it is correct (The Key): “Submit” is a momentary, completed action representing a deadline.
- Error Analysis: (a) until (Common Mistake). (c) in (Structural Error: “In” is used with months/years or durations like “in 2 hours”). (d) during (Meaning Trap: Lacks the strict deadline enforcement required by the library).
5 (a) until
- Why it is correct (The Key): “Wait” is a continuous action. You will continue the action of waiting up to the point when the archivist arrives.
- Error Analysis: (c) by (Common Mistake). (b) by the time (Meaning Trap: “Wait by the time” is grammatically incorrect; it must be “until”). (d) as (Structural Error).
6 (d) by
- Why it is correct (The Key): “Receive” is a completed action. The library must have the book in its possession no later than the deadline.
- Error Analysis: (a) until (Common Mistake: You cannot continuously receive a single item). (c) at (Meaning Trap). (b) in (Structural Error).
7 (b) until
- Why it is correct (The Key): Negative continuous state. “Cannot take” describes a restricted state that lasts up to the moment the waiver is signed.
- Error Analysis: (a) by (Common Mistake). (c) by the time (Structural Error: Clunky and alters the exact prerequisite meaning). (d) to (Structural Error).
8 (a) until / by
- Why it is correct (The Key): “Is valid” is an ongoing state (until Monday). “Collect” is a punctual action that must be completed before the deadline expires (by then).
- Error Analysis: (b) by / until (Meaning Trap: Reverses the logic entirely). (c) until / until (Common Mistake: You cannot continuously collect). (d) to / at (Structural Error).
9 (b) until / by
- Why it is correct (The Key): “Hold” is a continuous state of possession (until 3 PM). “Arrive” is a momentary action that must happen before the deadline (by that time).
- Error Analysis: (c) by / until (Meaning Trap). (a) by / by (Common Mistake: You cannot hold something ‘by’ a time; holding is continuous). (d) until / at (Meaning Trap: “At” is too restrictive; arriving at 2:50 PM is also acceptable).
10 (c) until
- Why it is correct (The Key): “Do not leave” is a continuous state of staying. It lasts up to the point the condition is met.
- Error Analysis: (a) by (Common Mistake). (b) during (Structural Error: Used with noun phrases, not clauses). (d) by the time (Meaning Trap: Changes the direct cause-and-effect condition).
11 (c) by
- Why it is correct (The Key): “Be returned” is a completed action representing a strict deadline.
- Error Analysis: (a) until (Common Mistake). (d) at (Meaning Trap: ‘At’ means returning it exactly at 4:00:00 PM, whereas ‘by’ allows returning it anytime before 4:00 PM). (b) for (Structural Error).
12 (b) until
- Why it is correct (The Key): “Use” is an ongoing action that is permitted for a duration up to the closing time.
- Error Analysis: (c) by (Common Mistake: “Use by” implies finishing the entire concept of usage, not the continuous act of sitting there). (a) when (Meaning Trap: Changes the permission window). (d) to (Structural Error).
13 (d) by
- Why it is correct (The Key): “Finish” is a momentary, completed action representing a deadline before the break begins.
- Error Analysis: (b) until (Common Mistake: You cannot continuously “finish” something over a long period). (a) during (Meaning Trap: Doing it during the break violates the rule to finish it before the break). (c) in (Structural Error).
14 (c) until
- Why it is correct (The Key): “Be unavailable” is a continuous state extending up to next Tuesday.
- Error Analysis: (a) by (Common Mistake). (b) within (Structural Error). (d) for (Structural Error: Requires a duration like “for three days”).
15 (a) until
- Why it is correct (The Key): “Not until” is an advanced inversion structure. The state of “not being granted access” lasts continuously up to the approval.
- Error Analysis: (b) by (Common Mistake: “Not by” does not trigger this grammatical inversion). (c) since (Structural Error). (d) when (Structural Error).
16 (b) by
- Why it is correct (The Key): “Be cleared” (paid off) is a completed action representing a deadline.
- Error Analysis: (d) until (Common Mistake). (a) to (Structural Error). (c) within (Structural Error: Requires a time span).
17 (c) until / by
- Why it is correct (The Key): “Remain” is a continuous state (until such time as). “Submit” is a punctual action requiring a deadline (by noon).
- Error Analysis: (a) by / until (Meaning Trap: Reverses the logic). (b) until / at (Meaning Trap: Submitting “at” noon doesn’t allow submitting before noon, which ‘by’ perfectly captures). (d) to / before (Structural Error: “To such time as” is incorrect English phrasing).
18 (d) until / by
- Why it is correct (The Key): “Stay open” is an ongoing state (until 10 PM). “Check out” is a completed, punctual action (by 8 PM).
- Error Analysis: (b) by / until (Meaning Trap). (a) until / until (Common Mistake). (c) to / in (Structural Error).
19 (a) until / by
- Why it is correct (The Key): The prohibition of photographing is a continuous state (until a license is secured). Acquiring the license is a completed action with a deadline (by the actual day).
- Error Analysis: (b) by / until (Meaning Trap). (c) by the time / on (Meaning Trap: “On” implies you can only get it that day, but “by” means you can get it earlier, which is logically safer for library prep). (d) unless / in (Structural Error).
20 (b) by / until
- Why it is correct (The Key): “Return” is a punctual action with a deadline (by the deadline). “Be revoked” establishes a new continuous state of lacking privileges (until further notice—a highly standard formal collocation).
- Error Analysis: (a) until / by (Meaning Trap: Reverses logic completely). (c) at / to (Structural Error). (d) within / for (Structural Error).
GRAMMAR POINTS TO REMEMBER
1 UNTIL (For States and Durations):
- Use Until to describe how long a situation continues. It is used with verbs that express an ongoing state or continuous action (e.g., keep, wait, stay, remain, use, hold, be open, be unavailable).
- Rule of thumb: If you can do the action continuously for 3 hours, use until.
- Example: “You can keep the book until Friday.” (The action of keeping happens on Monday, Tuesday, Wednesday, Thursday, and stops on Friday).
2 BY (For Deadlines and Completed Actions):
- Use By to indicate a deadline. It means “at or before a specific time.” It is used with punctual verbs that describe a momentary, finished action (e.g., return, submit, finish, arrive, clear, receive).
- Rule of thumb: If the action only takes a second to complete, use by.
- Example: “You must return the book by Friday.” (The action of handing the book over happens once, before Friday arrives).
3 Negative States:
- When an action is prohibited, the prohibition itself is a continuous state, so we use until.
- Example: “Do not leave the desk until the librarian checks the pages.”
4 Advanced Structures:
- Until further notice: A very common formal phrase meaning a state will continue indefinitely until someone announces a change.
- Not until… will/do/does: When a sentence begins with “Not until”, the main clause must use inverted question word order (e.g., Not until she approves will you enter).