By vs. Until – English Grammar Exercises for B2
Read the doctor’s strict medical advice to a patient regarding their antibiotic prescription and recovery timeline. Choose the best option to complete the sentences.
1 “You need to stay in bed and get plenty of rest ______ Monday morning to give your immune system a chance to fight.”
(a) by
(b) until
(c) within
(d) at
2 “If you take these pills correctly, the high fever should completely disappear ______ tomorrow evening.”
(a) until
(b) for
(c) by
(d) during
3 “Whatever you do, do not stop taking this medication ______ the bottle is entirely empty.”
(a) by
(b) until
(c) to
(d) in
4 “You will have finished the entire course of these strong antibiotics ______ next Friday.”
(a) until
(b) during
(c) at
(d) by
5 “Please rest your voice and drink warm herbal tea ______ the inflammation in your throat goes down.”
(a) by
(b) within
(c) until
(d) since
6 “Your throat will definitely feel much better ______ the time you wake up tomorrow morning.”
(a) until
(b) to
(c) by
(d) as
7 “You must remain isolated in your bedroom ______ your blood test results come back negative.”
(a) by
(b) until
(c) in
(d) by the time
8 “Don’t worry if you still feel sick now; the medication will start taking effect ______ 8:00 PM tonight at the latest.”
(a) until
(b) by
(c) for
(d) at
9 “I want you to continue drinking plenty of fluids ______ the weekend to flush out the bacteria.”
(a) until
(b) by
(c) by the time
(d) within
10 “If your temperature does not drop below 38 degrees Celsius ______ midnight, please go straight to the emergency room.”
(a) until
(b) during
(c) in
(d) by
11 “Keep applying this antibiotic ointment to the wound twice a day ______ the redness is completely gone.”
(a) by
(b) until
(c) at
(d) within
12 “With strict adherence to this treatment, the bacterial infection will have cleared up ______ the end of the week.”
(a) until
(b) in
(c) by
(d) to
13 “You must avoid eating any solid or spicy foods ______ tomorrow; however, your stomach will have fully settled ______ then.”
(a) by / until
(b) until / by
(c) by / by
(d) until / until
14 “Do not return to your stressful office job ______ you are 100% symptom-free.”
(a) by
(b) within
(c) until
(d) at
15 “We expect your dangerously high white blood cell count to drop back to normal levels ______ your next check-up.”
(a) until
(b) during
(c) by
(d) since
16 “Please wear this medical mask around your family members ______ I officially tell you it is safe to remove it.”
(a) by
(b) until
(c) to
(d) in
17 “You will likely experience severe fatigue ______ Wednesday, but your normal energy levels will return ______ the weekend.”
(a) until / by
(b) by / until
(c) for / at
(d) at / by
18 “The severe chest coughing should drastically subside ______ the third day of your medical treatment.”
(a) by
(b) until
(c) by the time
(d) as
19 “I will keep you connected to this IV drip ______ all the fluids are completely administered.”
(a) until
(b) during
(c) by
(d) to
20 “It is crucial that you wait ______ the nausea passes before you drive; it should completely fade away ______ 3:00 PM.”
(a) by / until
(b) until / until
(c) until / by
(d) by / by
ANSWER KEY & EXPLANATIONS
1 (b) until
- Why it is correct (The Key): “Stay in bed” is a continuous state of resting. Until is used to show how long an ongoing action continues before it stops.
- Error Analysis: (a) by (Common Mistake: You cannot continuously stay in bed “by” a time; by is for single, completed actions). (c) within (Structural Error: Requires a duration, like “within 3 days”). (d) at (Meaning Trap: “At” means getting into bed exactly on Monday morning, which contradicts the doctor’s advice to rest now).
2 (c) by
- Why it is correct (The Key): “Disappear” is a punctual, completed action. It serves as a strict deadline or expected completion time, meaning the fever will be gone at or before tomorrow evening.
- Error Analysis: (a) until (Common Mistake: A fever cannot continuously “disappear” over a period of time). (b) for (Structural Error). (d) during (Meaning Trap: Lacks the completion/deadline enforcement).
3 (b) until
- Why it is correct (The Key): When a punctual action is negated (“do not stop”), it creates a continuous state of continuing the action. This state of taking pills lasts until the condition (the bottle is empty) 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): “Have finished” is the Future Perfect tense, which describes a completed action. The doctor sets a deadline for this completion.
- Error Analysis: (a) until (Common Mistake: You cannot continuously “have finished” something). (b) during (Meaning Trap). (c) at (Meaning Trap: Allows no flexibility, whereas “by” means it can be finished earlier).
5 (c) until
- Why it is correct (The Key): “Rest your voice” is an ongoing, continuous process. The resting continues up to the time the inflammation reduces.
- 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): “Feel much better” acts as a conclusive milestone or achievement here. The healing will be completed no later than the time the patient wakes up.
- Error Analysis: (a) until (Common Mistake: “Feel better until you wake up” means the patient will feel sick after waking up, which reverses the medical logic). (b) to (Structural Error). (d) as (Structural Error).
7 (b) until
- Why it is correct (The Key): “Remain isolated” is a continuous state. The patient will maintain this isolation up to the moment the test results arrive.
- Error Analysis: (a) by (Common Mistake). (c) in (Structural Error). (d) by the time (Meaning Trap: Grammatically incorrect here without a perfect tense).
8 (b) by
- Why it is correct (The Key): “Start taking effect” is a punctual milestone. It represents the deadline for the medicine to work.
- Error Analysis: (a) until (Common Mistake: The medicine cannot continuously “start”). (c) for (Structural Error). (d) at (Meaning Trap: “At” means exactly at 8:00 PM, but “by” includes the possibility of it working earlier).
9 (a) until
- Why it is correct (The Key): “Continue drinking” is explicitly an ongoing action.
- Error Analysis: (b) by (Common Mistake). (c) by the time (Structural Error). (d) within (Structural Error).
10 (d) by
- Why it is correct (The Key): “Drop below 38 degrees” indicates a completed state/achievement. It must reach this state before the midnight deadline to avoid the emergency room.
- Error Analysis: (a) until (Common Mistake). (b) during (Meaning Trap). (c) in (Structural Error).
11 (b) until
- Why it is correct (The Key): “Keep applying” is an ongoing action.
- Error Analysis: (a) by (Common Mistake). (c) at (Meaning Trap). (d) within (Structural Error).
12 (c) by
- Why it is correct (The Key): “Will have cleared up” describes a completed state of healing before a specific future time.
- Error Analysis: (a) until (Common Mistake). (b) in (Structural Error). (d) to (Structural Error).
13 (b) until / by
- Why it is correct (The Key): “Avoid eating” is a continuous state of fasting (until tomorrow). “Have fully settled” is a conclusive achievement representing a deadline for recovery (by then).
- Error Analysis: (a) by / until (Meaning Trap: Reverses the logic). (c) by / by (Common Mistake). (d) until / until (Common Mistake).
14 (c) until
- Why it is correct (The Key): The negative “Do not return” creates a state of staying home. The patient must wait at home until the symptoms are completely gone.
- Error Analysis: (a) by (Common Mistake). (b) within (Structural Error). (d) at (Structural Error).
15 (c) by
- Why it is correct (The Key): “Drop back to normal” is a momentary action of completion (a medical milestone). It must happen before the check-up.
- Error Analysis: (a) until (Common Mistake). (b) during (Meaning Trap). (d) since (Structural Error).
16 (b) until
- Why it is correct (The Key): “Wear this mask” is an ongoing state that must be maintained up to the doctor’s verbal approval.
- Error Analysis: (a) by (Common Mistake: You cannot continuously wear a mask “by” a time). (c) to (Structural Error). (d) in (Structural Error).
17 (a) until / by
- Why it is correct (The Key): “Experience fatigue” is a continuous symptom (until Wednesday). “Energy will return” is the punctual, final completion of recovery (by the weekend).
- Error Analysis: (b) by / until (Meaning Trap: Reverses the logic). (c) for / at (Structural Error). (d) at / by (Structural Error).
18 (a) by
- Why it is correct (The Key): “Subside” (to become less intense) acts as a medical milestone/completion point. It will be achieved before the deadline of the third day.
- Error Analysis: (b) until (Common Mistake). (c) by the time (Structural Error). (d) as (Structural Error).
19 (a) until
- Why it is correct (The Key): “Keep you connected” is an ongoing medical procedure. It stops when the condition (all fluids administered) is fulfilled.
- Error Analysis: (c) by (Common Mistake). (b) during (Meaning Trap). (d) to (Structural Error).
20 (c) until / by
- Why it is correct (The Key): “Wait” is a continuous action (until nausea passes). “Completely fade away” is the punctual, final achievement representing the deadline for the symptom (by 3:00 PM).
- Error Analysis: (a) by / until (Meaning Trap). (b) until / until (Common Mistake). (d) by / by (Common Mistake).
GRAMMAR POINTS TO REMEMBER
1 UNTIL (For Medical Care and Symptoms):
- Use Until to define the duration of an ongoing action, habit, or state. In a medical context, it describes how long you must maintain a treatment, rest, or endure a symptom. It answers: How long must I keep doing this before I can stop?
- Key Verbs: rest, stay (in bed), keep (taking pills), remain (isolated), wait, continue, experience.
- Example: “You must rest until the fever breaks.” (You must continuously perform the action of resting for the entire duration).
2 BY (For Recovery Milestones and Deadlines):
- Use By to indicate a strict deadline or a point of completion in the future. It is used by doctors to predict when a symptom will disappear or a medicine will take effect. It answers: What is the latest possible time this change will happen? (It means “no later than”).
- Key Verbs: disappear, finish, clear up, take effect, return (to normal), drop, subside.
- Example: “The infection will clear up by Friday.” (The healing process will be entirely completed before Friday arrives).
3 The “Do Not” Waiting Rule in Prescriptions:
- When a doctor tells you not to do a momentary action (e.g., “Do not stop taking the medicine,” “Do not return to work”), it creates a continuous state of restriction. Therefore, you must use until.
- Example: “Do not stop the antibiotics until the bottle is empty.” (Maintain the state of taking them up to that exact moment).