By vs. Until – English Grammar Exercises for B2
Cramming for Exams – A stressed student complains about pulling an all-nighter and the ultimate relief of submitting the test.
Choose the most appropriate word or phrase to complete each sentence. Pay close attention to whether the verb describes a continuous action (like studying or staying awake) or an action that must be completed at a specific deadline (like finishing or submitting).
1 I stayed awake staring blankly at my biology textbook ______ 4:00 AM this morning.
(a) by
(b) until
(c) by the time
(d) to
2 ______ the time the sun finally came up, I had already drunk four massive cups of black coffee.
(a) Until
(b) By
(c) In
(d) At
3 I desperately need to memorize these complex formulas ______ the exam begins at 9:00 AM.
(a) until
(b) by
(c) to
(d) at the time
4 I kept highlighting my lecture notes non-stop ______ the ink in my yellow marker completely ran out.
(a) until
(b) by
(c) by the time
(d) during
5 I promised myself that I would finish reading chapter five ______ 2:00 AM, but I failed miserably.
(a) until
(b) for
(c) by
(d) to
6 I refuse to close my eyes and go to sleep ______ I fully understand this macroeconomic concept.
(a) by
(b) to
(c) until
(d) by the time
7 The professor strictly stated that we must submit the final essay ______ 11:59 PM tonight.
(a) until
(b) at
(c) by
(d) on
8 I didn’t stop typing my history assignment ______ my fingers literally started cramping.
(a) by
(b) until
(c) by the time
(d) during
9 ______ midnight, I had only reviewed half of the syllabus and panic started to set in.
(a) Until
(b) In
(c) By
(d) To
10 I was frantically cramming vocabulary words into my brain ______ the very last minute before entering the hall.
(a) by
(b) for
(c) until
(d) by the time
11 We studied intensely in the campus library ______ the security guard turned off the lights and kicked us out.
(a) by
(b) to
(c) until
(d) by the time
12 ______ the time the professor handed out the test paper, my mind had gone completely blank from exhaustion.
(a) Until
(b) By
(c) At
(d) On
13 The intense anxiety sitting in my chest didn’t fade away ______ I finally walked out of the examination room.
(a) by
(b) until
(c) by the time
(d) since
14 I am absolutely certain that ______ tomorrow morning, I will have forgotten everything I memorized tonight.
(a) until
(b) in
(c) to
(d) by
15 My roommate was snoring so loudly, but I had no choice but to keep studying ______ dawn.
(a) by
(b) until
(c) by the time
(d) to
16 Please make sure you have successfully uploaded your project to the portal ______ the deadline tomorrow.
(a) until
(b) at
(c) by
(d) during
17 I honestly felt like a walking zombie ______ I pressed the ‘submit’ button and the screen said ‘Done’.
(a) by
(b) by the time
(c) to
(d) until
18 ______ the time I realized I was studying the wrong chapter, it was already 5:30 AM.
(a) Until
(b) In
(c) By
(d) At
19 I won’t feel any true relief ______ I log in and see my final passing grade on the student portal.
(a) by
(b) until
(c) by the time
(d) during
20 I had confidently answered all the multiple-choice questions ______ the warning bell rang for the last five minutes.
(a) by the time
(b) until
(c) to
(d) at
ANSWER KEY & EXPLANATIONS
1 (b) until
- Why it is correct: The action “stayed awake” is a continuous state. It lasted continuously up to the specific time of 4:00 AM and then stopped.
- Distractor Analysis: (a) “by” is a common mistake (used for deadlines of completed actions, not continuous states). (c) “by the time” is a strong distractor (must be followed by a Subject + Verb clause, not a specific hour). (d) “to” is a structural error.
2 (b) By
- Why it is correct: Combined with “the time”, it forms the phrase “By the time” (meaning ‘no later than’). The action of drinking four cups of coffee was completed (had drunk – Past Perfect) before the sun came up.
- Distractor Analysis: (a) “Until” is a common mistake (does not form a proper collocation here). (c) “In”, (d) “At” are structural errors.
3 (b) by
- Why it is correct: The act of “memorizing formulas” needs to be completed (a deadline) before the exam begins at 9:00 AM.
- Distractor Analysis: (a) “until” is a common mistake (you cannot continuously memorize right up until the exam starts and then stop; the goal is to have the task finished before that time). (c) “to” is a structural error. (d) “at the time” implies the wrong meaning.
4 (a) until
- Why it is correct: “Kept highlighting” is a continuous action, which only ended when the marker’s ink ran out.
- Distractor Analysis: (b) “by”, (c) “by the time” are used for completion deadlines, not for maintaining an action. (d) “during” must be followed by a noun phrase indicating a period, not a full clause.
5 (c) by
- Why it is correct: “Finish” is an instantaneous verb indicating completion. Finishing chapter five must be done before the deadline of 2:00 AM.
- Distractor Analysis: (a) “until” is a common mistake (you cannot “finish continuously”). (b) “for”, (d) “to” are incorrect prepositions.
6 (c) until
- Why it is correct: The state of “refusing to go to sleep” will be maintained continuously up to the point the concept is fully understood.
- Distractor Analysis: (a) “by”, (b) “to”, (d) “by the time” are structural and contextual errors.
7 (c) by
- Why it is correct: “Submit” is an instantaneous action requiring a deadline. The deadline is 11:59 PM.
- Distractor Analysis: (a) “until” is a common mistake (you cannot continuously submit an essay for hours). (b) “at” means submitting exactly at the stroke of 11:59 PM, whereas ‘by’ means submitting before or no later than that time, which is more logical for a deadline. (d) “on” is used for days/dates.
8 (b) until
- Why it is correct: The typing action (“didn’t stop typing”) was maintained continuously until the physical consequence (cramping) occurred.
- Distractor Analysis: (a) “by”, (c) “by the time”, (d) “during” are grammatical errors in this context.
9 (c) By
- Why it is correct: The action of “reviewing half of the syllabus” was completed (had reviewed – Past Perfect) before the deadline of midnight.
- Distractor Analysis: (a) “Until” is incorrect (it is rarely used with perfect tenses when summarizing a completed result). (b) “In”, (d) “To” are incorrect prepositions.
10 (c) until
- Why it is correct: “Cramming” is an intense, continuous action extending right up to the very last minute.
- Distractor Analysis: (a) “by”, (b) “for”, (d) “by the time” are contextual and structural errors.
11 (c) until
- Why it is correct: The action “studied” occurred continuously and was forcefully terminated by the security guard turning off the lights.
- Distractor Analysis: (a) “by”, (b) “to”, (d) “by the time” are grammatical errors.
12 (b) By
- Why it is correct: The structure “By the time + Subject + Verb”. The action of the mind going completely blank (had gone blank) was completed before the professor handed out the paper.
- Distractor Analysis: (a) “Until”, (c) “At”, (d) “On” do not form the correct prepositional phrase here.
13 (b) until
- Why it is correct: The state of anxiety (“didn’t fade away”) lingered continuously until the student physically walked out of the room.
- Distractor Analysis: (a) “by”, (c) “by the time”, (d) “since” convey the wrong meaning.
14 (d) by
- Why it is correct: The Future Perfect tense (will have forgotten) always pairs with “By + time” to indicate an action will be completed no later than a certain point in the future.
- Distractor Analysis: (a) “until”, (b) “in”, (c) “to” are grammatical errors.
15 (b) until
- Why it is correct: “Keep studying” is a continuous action lasting uninterrupted until dawn.
- Distractor Analysis: (a) “by”, (c) “by the time”, (d) “to” are structural errors.
16 (c) by
- Why it is correct: “Upload” is a task that needs to be completed before a designated deadline.
- Distractor Analysis: (a) “until” is a common mistake (you cannot upload continuously). (b) “at”, (d) “during” lack the specific deadline nuance.
17 (d) until
- Why it is correct: Feeling like a “walking zombie” is a continuous state lasting exactly up to the moment the submit button is pressed.
- Distractor Analysis: (a) “by”, (b) “by the time”, (c) “to” convey the wrong meaning.
18 (c) By
- Why it is correct: “By the time + Subject + Verb”: No later than the moment of realizing the mistake, the time WAS ALREADY 5:30 AM.
- Distractor Analysis: (a) “Until”, (b) “In”, (d) “At” are structural errors.
19 (b) until
- Why it is correct: The state of “not feeling true relief” will continue uninterrupted up to the exact point of seeing the passing grade.
- Distractor Analysis: (a) “by”, (c) “by the time”, (d) “during” are contextual errors.
20 (a) by the time
- Why it is correct: It is followed by a clause (the warning bell rang), and the main clause uses the Past Perfect (had confidently answered) to indicate completion before that event. Therefore, “by the time” is required.
- Distractor Analysis: (b) “until” conflicts with the perfect tense grammar. (c) “to”, (d) “at” are incorrect prepositions.
GRAMMAR POINTS TO REMEMBER
To score perfectly when distinguishing between By and Until, especially in the context of exams or deadlines, remember these two golden rules:
1 UNTIL – CONTINUOUS ENDURANCE
- Nature: Used to describe an action or a state that is CONTINUOUS and only ceases at a specific point in time.
- Identifying Signs: Often paired with verbs indicating maintenance such as: wait, stay awake, study, keep doing, didn’t stop. Or continuous emotions/states: didn’t fade, refuse to.
- Example: I stayed awake until 4 AM. (The action of staying awake was continuous and stopped exactly at 4 AM).
2 BY (No later than) – COMPLETION DEADLINE
- Nature: Used to establish a DEADLINE. The action doesn’t need to be continuous; it merely needs to be COMPLETED at or before that time marker.
- Identifying Signs: Often paired with verbs indicating finality: finish, submit, upload, arrive. It is incredibly common with Perfect tenses (Past Perfect / Future Perfect).
- Example: I had finished chapter 3 by 4 AM. (It is unknown exactly when the studying finished, only that it was successfully completed no later than 4 AM).
- Expanded Structure Note: By the time + Clause (Subject + Verb) means “No later than the moment that…”. It is used to connect two events, showing that one event was completed before the other occurred. Like ‘By’, it frequently accompanies Perfect tenses. (Note: ‘Until the time’ is generally not used in this way).