Can vs. Could – English Grammar Exercises for A2
You are invited to a friend’s house for dinner. You are messaging them to explain what you are allowed to eat and what you are allergic to. Read the sentences carefully and choose the best option (A, B, C, or D) to complete your messages.
1 “Thank you for the invitation! I must tell you that I ______ eat peanuts because I am severely allergic to them.”
(A) can’t
(B) couldn’t
(C) don’t can
(D) not can
2 “When I was a kid, I ______ eat ice cream every day, but now dairy makes my stomach hurt.”
(A) can
(B) could
(C) can’t
(D) am could
3 “I am a strict vegan now, which means I ______ eat any meat, eggs, or animal products.”
(A) couldn’t
(B) can’t
(C) haven’t can
(D) don’t can
4 “Host: ______ you eat spicy food? I am planning to make a hot curry.”
(A) Do you can
(B) Could you
(C) Can
(D) Are you can
5 “My doctor says I am pre-diabetic, so I ______ eat a lot of sugar anymore. A sugar-free dessert would be great.”
(A) couldn’t
(B) can to not
(C) can’t
(D) don’t can
6 “Last year, I ______ eat bread because I was on a strict diet, but now I am allowed to eat it.”
(A) can’t
(B) couldn’t
(C) wasn’t can
(D) didn’t could
7 “Please be careful with the menu. My wife ______ eat seafood. If she eats shrimp, she has to go to the hospital!”
(A) cannot
(B) could
(C) not can
(D) don’t can
8 “Host: I am baking a cake for us. ______ I use regular flour, or do you need gluten-free?”
(A) Could to
(B) Can
(C) Am I can
(D) Do I can
9 “Ten years ago, my grandfather ______ eat anything, but now his teeth are very weak.”
(A) can
(B) could
(C) can’t
(D) could to
10 “I have a mild dairy intolerance. I ______ eat a little bit of butter, but drinking a glass of milk makes me sick.”
(A) could to
(B) can
(C) cans
(D) am can
11 “Please wash the salad bowl carefully. My daughter ______ touch walnuts at all; it is highly dangerous for her.”
(A) couldn’t
(B) doesn’t can
(C) can’t
(D) not can
12 “Before I found out about my allergy, I ______ understand why I always felt sick after meals.”
(A) can’t
(B) couldn’t
(C) didn’t can
(D) wasn’t can
13 “Because of my religion, I ______ eat pork. Do you have chicken or beef instead?”
(A) don’t can
(B) could
(C) can’t
(D) am not can
14 “I ______ eat onions. I am not allergic to them, I just really hate the taste!”
(A) can
(B) could
(C) cans
(D) am can
15 “Host: What about your brother? ______ he eat tomatoes?”
(A) Does he can
(B) Can
(C) Is he can
(D) Could he to
16 “When I had a bad sore throat last week, I ______ swallow any solid food.”
(A) can’t
(B) couldn’t
(C) didn’t could
(D) don’t can
17 “I am on a low-carb diet right now, so I ______ only eat meat and green vegetables.”
(A) can
(B) could
(C) can to
(D) cans
18 “Thank you for asking about my diet! Don’t worry, I ______ eat almost everything.”
(A) could
(B) can
(C) am can
(D) can to
19 “I ______ drink coffee in the evening, or I will stay awake all night long.”
(A) couldn’t
(B) can’t
(C) don’t can
(D) not can
20 “I used to be a vegetarian, so I ______ eat meat for five years, but I enjoy eating it now.”
(A) couldn’t
(B) can’t
(C) didn’t can
(D) wasn’t could
ANSWER KEY & EXPLANATIONS
1 Key: (A) can’t
Explanation: – Why it’s correct: Being allergic is a present physical fact. “Can’t” expresses this present inability.
- Why others are wrong: (B) “Couldn’t” is for the past. (C) “Don’t can” and (D) “Not can” are grammatically invalid (modals do not use “do/don’t”).
2 Key: (B) could
Explanation: – Why it’s correct: “When I was a kid” indicates a past ability. “Could” is the past tense of “can”.
- Why others are wrong: (A) “Can” is present tense. (C) “Can’t” contradicts the sentence. (D) “Am could” is invalid grammar.
3 Key: (B) can’t
Explanation: – Why it’s correct: Being a vegan is a present rule/restriction.
- Why others are wrong: (A) “Couldn’t” is for the past. (C) and (D) use auxiliary verbs (“haven’t”, “don’t”) which are never used with “can”.
4 Key: (C) Can
Explanation: – Why it’s correct: To ask a question about someone’s present physical ability/diet, we just invert the modal: “Can you…?”
- Why others are wrong: (A) and (D) incorrectly use “Do” and “Are”. (B) “Could you” is generally used to make polite requests (“Could you pass the salt?”), not to ask about factual dietary limits.
5 Key: (C) can’t
Explanation: – Why it’s correct: A present restriction given by a doctor.
- Why others are wrong: (B) We never put “to” after “can”. (A) is past tense. (D) uses “don’t”.
6 Key: (B) couldn’t
Explanation: – Why it’s correct: “Last year” means this was a past restriction. “Couldn’t” is the negative past form of “can”.
- Why others are wrong: (A) is present tense. (C) and (D) incorrectly use “wasn’t” and “didn’t” with a modal verb.
7 Key: (A) cannot
Explanation: – Why it’s correct: “Cannot” is the formal, full-word version of “can’t”. It describes a present, highly dangerous allergy.
- Why others are wrong: (B) is past tense. (C) and (D) are invalid structures.
8 Key: (B) Can
Explanation: – Why it’s correct: Asking about present permission/options.
- Why others are wrong: (A) “Could to” is invalid. (C) and (D) incorrectly use “Am” and “Do”.
9 Key: (B) could
Explanation: – Why it’s correct: “Ten years ago” indicates past ability.
- Why others are wrong: (A) is present tense. (C) is present and contradicts the meaning. (D) adds an illegal “to”.
10 Key: (B) can
Explanation: – Why it’s correct: A factual statement about what is physically possible for the speaker right now.
- Why others are wrong: (A) has an illegal “to”. (C) “Cans” is a major mistake; modals never take an “-s” for he/she/it or any subject. (D) uses “am”.
11 Key: (C) can’t
Explanation: – Why it’s correct: A present, life-threatening restriction.
- Why others are wrong: (A) is past tense. (B) “Doesn’t can” is a common but huge mistake (never use do/does with can).
12 Key: (B) couldn’t
Explanation: – Why it’s correct: “Before I found out” places this situation in the past. “Couldn’t” shows the past inability to understand.
- Why others are wrong: (A) is present tense. (C) and (D) use incorrect auxiliary verbs (“didn’t”, “wasn’t”).
13 Key: (C) can’t
Explanation: – Why it’s correct: A religious diet is a present restriction.
- Why others are wrong: (A) and (D) are invalid. (B) is past tense.
14 Key: (A) can
Explanation: – Why it’s correct: The speaker has the physical ability to eat onions right now, they just choose not to.
- Why others are wrong: (C) “Cans” is invalid (no “-s” on modals). (B) is past. (D) uses “am”.
15 Key: (B) Can
Explanation: – Why it’s correct: Asking a question about “he”. We just put “Can” at the front.
- Why others are wrong: (A) “Does he can” is completely invalid. Never use “does” to make a question with “can”.
16 Key: (B) couldn’t
Explanation: – Why it’s correct: “Last week” indicates a temporary past inability due to illness.
- Why others are wrong: (A) is present tense. (C) “Didn’t could” is invalid.
17 Key: (A) can
Explanation: – Why it’s correct: Expressing a present limitation due to a current diet (“right now”).
- Why others are wrong: (B) is past tense. (C) adds an illegal “to”. (D) adds an illegal “-s”.
18 Key: (B) can
Explanation: – Why it’s correct: A present statement of broad dietary ability.
- Why others are wrong: (A) is past. (C) and (D) are structural errors.
19 Key: (B) can’t
Explanation: – Why it’s correct: A present physical limitation regarding caffeine.
- Why others are wrong: (A) is past. (C) and (D) are invalid grammar.
20 Key: (A) couldn’t
Explanation: – Why it’s correct: The five years of being a vegetarian happened in the past (“used to be”).
- Why others are wrong: (B) is present. (C) and (D) use invalid auxiliaries (“didn’t”, “wasn’t”).
GRAMMAR POINTS TO REMEMBER
- Present Ability and Restriction (Can / Can’t):
- We use can to say that we have the ability, permission, or health to eat something right now.
- We use can’t (or cannot) to state a present physical limit, like an allergy or a strict diet.
- Example: “I can’t eat peanuts.” (It is a fact about my body today).
- Past Ability and Restriction (Could / Couldn’t):
- We use could and couldn’t to talk about limits we had in the past (when we were children, or before we started a diet).
- Example: “Last year, I couldn’t eat bread, but now I can.”
- The 3 Golden Rules of Modal Verbs:
- Rule 1: No “TO”. Never put “to” after can or could. (Say: I can eat, NEVER I can to eat).
- Rule 2: No “-S”. Modal verbs never change form. Do not add “-s” for he, she, or it. (Say: He can eat, NEVER He cans eat).
- Rule 3: No “DO/DOES/DID”. Modals are strong enough to make their own negatives and questions.
- Negative: Say I can’t, NEVER I don’t can.
- Question: Say Can you eat?, NEVER Do you can eat?