By vs. Until – English Grammar Exercises for B2
Read the party organizer’s secret text messages to the friend who is tasked with distracting the birthday boy. Choose the best option to complete the sentences.
1 “Your mission is simple: keep David busy at the coffee shop ______ I text you the secret code word.”
(a) by
(b) until
(c) within
(d) at
2 “I promise the rest of the team will have all the balloons inflated and hung up ______ 6:30 PM.”
(a) until
(b) for
(c) by
(d) during
3 “Whatever you do, do not let him drive back to the house ______ the surprise is fully ready.”
(a) by
(b) until
(c) to
(d) in
4 “The bakery guaranteed that the custom birthday cake will be delivered ______ 5:00 PM at the latest.”
(a) until
(b) during
(c) at
(d) by
5 “Please distract him ______ sunset so we have enough darkness to turn on the fairy lights in the garden.”
(a) by
(b) within
(c) until
(d) since
6 “We need to get all thirty guests completely hidden in the living room ______ the time he opens the front door.”
(a) until
(b) to
(c) by
(d) as
7 “Just walk around the shopping mall with him ______ I give you the signal to come back.”
(a) by
(b) until
(c) in
(d) by the time
8 “I have to finish setting up the DJ booth ______ the first wave of guests starts arriving.”
(a) until
(b) by
(c) for
(d) at
9 “Make sure you guys stay completely out of our neighborhood ______ at least 7:00 PM.”
(a) until
(b) by
(c) by the time
(d) within
10 “All the guests’ cars must be parked at the end of the street ______ 6:45 PM so he doesn’t get suspicious when you drive up.”
(a) until
(b) during
(c) in
(d) by
11 “Keep talking to him about his favorite video games ______ we get the projector screen working.”
(a) by
(b) until
(c) at
(d) within
12 “If you can delay his return ______ 8:00 PM, our preparation will be absolutely flawless.”
(a) until
(b) in
(c) by
(d) to
13 “We must wrap all these massive presents and hide the boxes ______ he finishes his gym session.”
(a) until / by
(b) by
(c) during
(d) until
14 “I will not light the candles on the cake ______ you confirm that you are exactly one block away.”
(a) by
(b) within
(c) until
(d) at
15 “If he asks to go home early, just lie and say there is heavy traffic, so you guys won’t make it back ______ 8:30 PM anyway.”
(a) until
(b) during
(c) by
(d) since
16 “The catering team should have the buffet completely set up ______ 7:15 PM so the food stays warm.”
(a) by
(b) until
(c) to
(d) in
17 “You need to act completely normal and pretend nothing is happening ______ everyone suddenly yells ‘Surprise!'”
(a) until
(b) by
(c) for
(d) at
18 “We will have the entire backyard transformed into a tropical dance floor ______ tonight.”
(a) until
(b) in
(c) by
(d) to
19 “Please keep him occupied ______ 6 PM; I swear we will have everything perfectly set up ______ then.”
(a) by / until
(b) until / by
(c) by / by
(d) until / until
20 “We cannot start playing the music ______ the guest of honor actually walks in, so make sure you bring him here ______ 8 PM sharp.”
(a) by / until
(b) until / until
(c) until / by
(d) by / by
ANSWER KEY & EXPLANATIONS
1 (b) until
- Why it is correct (The Key): “Keep David busy” is a continuous action (a holding pattern). Until marks the end of this ongoing activity.
- Error Analysis: (a) by (Common Mistake: You cannot continuously keep someone busy “by” a time; by is for single, completed actions). (c) within (Structural Error: Requires a duration like “within an hour”). (d) at (Meaning Trap: “At” means starting the action exactly then, which contradicts the goal).
2 (c) by
- Why it is correct (The Key): “Have all the balloons inflated” is a completed action/state. 6:30 PM is the strict deadline for this task to be finished.
- Error Analysis: (a) until (Common Mistake: You cannot continuously complete inflating balloons over the whole period). (b) for (Structural Error). (d) during (Meaning Trap: Lacks the “deadline” enforcement).
3 (b) until
- Why it is correct (The Key): When a punctual action is negated (“do not let him drive back”), it creates a continuous state of prevention or waiting. This state lasts until the condition (the surprise is ready) is met.
- Error Analysis: (a) by (Common Mistake). (c) to (Structural Error). (d) in (Structural Error).
4 (d) by
- Why it is correct (The Key): “Be delivered” is a momentary, completed action. The organizer sets a deadline for this to happen.
- Error Analysis: (a) until (Common Mistake: A cake cannot be continuously delivered for hours). (b) during (Meaning Trap: Vague, removes the deadline nuance). (c) at (Meaning Trap: “At” allows no flexibility, whereas “by” means it can arrive earlier).
5 (c) until
- Why it is correct (The Key): “Distract him” is an ongoing process. The distraction continues up to the time the sun sets.
- Error Analysis: (a) by (Common Mistake). (b) within (Structural Error). (d) since (Structural Error: Refers to the starting point in the past).
6 (c) by
- Why it is correct (The Key): “Get all guests hidden” is a verb phrase of completion. The action of hiding everyone must be finalized no later than the moment he opens the door.
- Error Analysis: (a) until (Common Mistake: You don’t hide them continuously up to the door opening; they must already be hidden before that point). (b) to (Structural Error). (d) as (Structural Error).
7 (b) until
- Why it is correct (The Key): “Walk around” is a continuous activity. The friend will maintain this action up to the signal.
- Error Analysis: (a) by (Common Mistake). (c) in (Structural Error). (d) by the time (Meaning Trap: While grammatically possible if the sentence were “You will have walked around by the time…”, the imperative “walk around” requires until).
8 (b) by
- Why it is correct (The Key): “Finish setting up” is a punctual achievement representing a strict deadline.
- Error Analysis: (a) until (Common Mistake: You cannot continuously “finish” something). (c) for (Structural Error). (d) at (Meaning Trap).
9 (a) until
- Why it is correct (The Key): “Stay out” is a continuous state of avoidance. The friend must maintain this distance until 7:00 PM.
- Error Analysis: (b) by (Common Mistake: “Stay by” is grammatically incorrect for describing the duration of staying away). (c) by the time (Structural Error). (d) within (Structural Error).
10 (d) by
- Why it is correct (The Key): “Be parked” indicates the completed state of the cars. They must reach this state before the deadline.
- Error Analysis: (a) until (Common Mistake). (b) during (Meaning Trap). (c) in (Structural Error).
11 (b) until
- Why it is correct (The Key): “Keep talking” is explicitly an ongoing action.
- Error Analysis: (a) by (Common Mistake). (c) at (Meaning Trap). (d) within (Structural Error).
12 (a) until
- Why it is correct (The Key): “Delay” means to make someone wait or to prolong an action. You maintain the delay until the target time.
- Error Analysis: (c) by (Common Mistake). (b) in (Structural Error). (d) to (Structural Error).
13 (b) by
- Why it is correct (The Key): “Wrap and hide” are completed actions serving as a deadline before he finishes the gym.
- Error Analysis: (d) until (Common Mistake). (a) until / by (Structural Error). (c) during (Meaning Trap).
14 (c) until
- Why it is correct (The Key): The negative “will not light” creates a state of waiting. The organizer waits to light the candles until the friend is close.
- Error Analysis: (a) by (Common Mistake). (b) within (Structural Error). (d) at (Structural Error).
15 (a) until
- Why it is correct (The Key): “Won’t make it back” functions as a negative state of travel/delay. They will remain away from home until 8:30 PM.
- Error Analysis: (c) by (Common Mistake: If you say “won’t make it back by 8:30”, it implies they will arrive after 8:30, which changes the specific party timeline instruction). (b) during (Meaning Trap). (d) since (Structural Error).
16 (a) by
- Why it is correct (The Key): “Have the buffet completely set up” is a momentary action of completion. It must be finalized before the deadline.
- Error Analysis: (b) until (Common Mistake). (c) to (Structural Error). (d) in (Structural Error).
17 (a) until
- Why it is correct (The Key): “Act normal” is an ongoing state that must be maintained up to the climax of the surprise.
- Error Analysis: (b) by (Common Mistake: You cannot continuously act normal by a time). (c) for (Structural Error). (d) at (Meaning Trap).
18 (c) by
- Why it is correct (The Key): “Have the backyard transformed” is the final, completed state required before the party starts.
- Error Analysis: (a) until (Common Mistake). (b) in (Structural Error). (d) to (Structural Error).
19 (b) until / by
- Why it is correct (The Key): “Keep him occupied” is a continuous distraction process (until 6 PM). “Have everything set up” is the punctual, final completion representing a deadline (by then).
- Error Analysis: (a) by / until (Meaning Trap: Reverses the logic). (c) by / by (Common Mistake). (d) until / until (Common Mistake).
20 (c) until / by
- Why it is correct (The Key): “Cannot start playing” is a state of waiting/delay (until he walks in). “Bring him here” is the punctual arrival acting as the deadline (by 8 PM sharp).
- Error Analysis: (a) by / until (Meaning Trap). (b) until / until (Common Mistake). (d) by / by (Common Mistake).
GRAMMAR POINTS TO REMEMBER
1 UNTIL (The Distraction / The Holding Pattern):
- Use Until to define the duration of an ongoing action or state. It is perfect for assigning “distraction” or “waiting” tasks. It answers: How long must I keep doing this before I can stop?
- Key Verbs: keep (busy/talking), wait, stay, delay, walk around, distract, hold off.
- Example: “Please distract him until I call you.” (You must continuously perform the action of distracting for the entire duration).
2 BY (The Setup / The Deadline):
- Use By to indicate a strict deadline for a completed action. It is used by the person rushing to finish the preparations. It answers: What is the latest possible time this task can be finished? (It means “no later than”).
- Key Verbs: finish, arrive, deliver, set up, hide, have [something] ready.
- Example: “We must finish decorating by 6 PM.” (The decoration process must be entirely completed before 6 PM hits).
3 The “Do Not” Waiting Rule:
- When you tell someone not to do a momentary action (e.g., “Do not let him drive back,” “I will not light the candles”), it creates a continuous state of waiting. Therefore, you must use until.
- Example: “Do not come home until the cake is ready.” (Maintain the state of staying away up to that exact moment).