Basics: Can and Could - Ability and Permission
The modal verbs can and could are essential for expressing what someone is able to do or allowed to do. We use can for present ability ("I can speak Spanish") and could to describe past ability ("I could run fast when I was younger"). They are also widely used to ask for, give, or deny permission, with could often acting as a more polite alternative to can ("Could I borrow your pen?" vs. "Can I go to the park?").
This challenge tests your understanding of these fundamental verbs in everyday contexts. You will explore scenarios involving past and present ability (such as a superhero's powers or a grandpa's youth), asking for and granting permission (like attending a concert or establishing roommate and house rules), and expressing inability or denial (like a spy who cannot reveal a secret).
You'll work through 12 questions in a variety of engaging formats, including single-choice, multi-choice, drop-down, and drag-and-drop.
Try the quiz to check your knowledge!
Drag the correct words to complete this millennial's diary entry about the perks of growing up.
"When I was ten, I could only watch one hour of television a day. Now that I live alone, I can eat ice cream for breakfast if I want to!"
"When I was ten, I could only watch one hour of television a day."
We use could to talk about permission in the past (what was allowed when the speaker was ten).
"Now that I live alone, I can eat ice cream for breakfast if I want to!"
We use can to talk about permission or freedom to do something in the present.
Complete the retired superhero's memoir by choosing the correct verbs.
When I was in my twenties, I ___ lift a bus with one hand, but now I ___ barely open a jar of pickles!
The correct answer is could / can.
We use could to talk about an ability in the past ("When I was in my twenties"), and can to talk about an ability in the present ("but now").
could
We use "could" to make polite requests. It is often paired with words like "possibly" or "please" to sound extra friendly and respectful.
can
We use "can" to state a present ability. The worker is explaining what they are currently physically able to do (lift heavy boxes).
Help the hungry roommate ask a polite question.
___ I please borrow your secret stash of chocolate? I promise to replace it tomorrow!
The correct answer is Could.
Could is used to ask for permission in a polite and friendly way. "Do," "Must," and "Am" are grammatically incorrect or inappropriate for asking permission in this context.
could
We use "could" to talk about a general ability we had in the past. Since Alex is talking about when they were five, the past tense modal is required.
can't
We use "can't" (cannot) to express a lack of ability in the present. Alex is talking about their memory "now," so the present tense negative modal is correct.
Help Grandpa finish his slightly exaggerated life story by dragging the correct verbs into the blanks.
"When I was twenty, I could lift a desk with one hand! But these days, I can't even lift this cup."
"When I was twenty, I could lift a car with one hand!"
We use could to talk about a general ability in the past.
"But these days, I can't even open this jar of pickles."
We use can't (or cannot) to talk about an inability in the present. Because Grandpa is talking about "these days," we use the present tense.
The correct answers are I can lift a car with one hand! and When I was a baby, I could fly around the nursery.
We use "can" for abilities in the present and "could" for abilities in the past. Remember that modal verbs are followed directly by a bare infinitive (a verb without "to"). "I can to shoot" is incorrect because of the "to," and "I could invisible" is missing the verb "be" (it should be "I can/could be invisible").
The correct answers are Can I borrow your neon sweater tonight? and Could I borrow your neon sweater tonight?
When asking for permission, both "can" and "could" are perfectly correct! "Can" is more informal and friendly, while "could" is a little more polite and soft. After modal verbs like "can" and "could," we always use the base form of the verb without "to" or any endings (borrow).
Help Agent 007-and-a-half finish his top-secret mission report by dragging the right words into the blanks.
"Yesterday, I couldn't sneak past the laser beams because I sneezed loudly. Now, the commander says I can't touch any of the explosive gadgets."
"Yesterday, I couldn't sneak past the laser beams because I sneezed loudly."
We use couldn't to describe an inability to do something in the past. The word "yesterday" is your clue!
"Now, the commander says I can't touch any of the explosive gadgets."
We use can't for a present lack of permission (prohibition). The commander "says" (present tense) that it is currently not allowed.
The correct answers are You can't sleep on the good sofa; it is exclusively mine. and When I was younger, I could catch three toy mice at once.
"Can't" (or cannot) is perfect for denying permission in the present, and "could" is used here to show a proud past ability. The incorrect options use the wrong verb forms after the modals: we never use an "-ing" word or a "to" infinitive immediately after "can," "could," "cannot," or "couldn't."
can
We use "can" to ask for permission in the present or future. "Do I please go" and "Am I please go" are grammatically incorrect.
could
We use "could" to talk about permission that was granted in the past. Because the teenager says "when she was my age," we know this refers to a past situation.
Choose the right word to complete the dramatic cat owner's warning to a guest.
You ___ sit on that velvet armchair. Sir Fluffington has claimed it as his throne, and he does not share.
The correct answer is can't.
We use can't (cannot) to deny permission in the present. "Couldn't" refers to the past, and "aren't" or "haven't" do not fit grammatically with the base verb "sit."
Modal verb
A modal verb is a special class of auxiliary — can, could, may, might, must, shall, should, will, would — that adds shades of meaning around possibility, ability, permission, obligation, or speculation. I can swim (ability), You should rest (advice), It might rain (possibility), You must leave (obligation).
Modals are grammatically peculiar: no -s in the third person (she can, not she cans), no infinitive, no participle, followed by the bare verb (I can swim, never I can to swim). Mastering them is the move from describing facts to expressing how you feel about them — likelihood, necessity, recommendation.
Questions
Questions in English are typically formed by inverting the subject and an auxiliary verb: She can dance → Can she dance?. When there's no auxiliary present, English adds do-support: The milk goes in the fridge → Does the milk go in the fridge?. The same pattern handles wh-questions (Where do you live?) and negative questions (Doesn't he know?).
The trickiest variant is indirect questions — I wonder where he is, not where is he. The inversion drops because the question is embedded inside another clause. Getting this right is one of the bigger jumps from A2 to B1 fluency.
Negation
Negation in English usually places not after the auxiliary or modal verb: I am not going, She does not know, You must not go. When there's no auxiliary, you add do-support: I go → I do not go. Most combinations contract: don't, can't, won't, isn't.
The trickiest rule for many learners: double negatives are not standard English. I didn't see nothing is non-standard; the standard forms are I saw nothing or I didn't see anything. Negative words like never, nobody, nothing already carry the negation — adding not on top doubles up.
English Grammar Basics
The English Grammar Basics tag marks quizzes and explainers covering the foundations of English grammar — nouns, verbs, adjectives, adverbs, prepositions, conjunctions, tenses, voice, mood, and basic sentence structure.
If you're starting out or rebuilding from scratch, this is the tag to follow: every challenge under it is designed to land the core rules without burying you in exceptions. Get the basics solid here and the more advanced topics — conditionals, reported speech, inversion — stop looking like a wall of new rules and start looking like extensions of what you already know.
A1 | Elementary | Beginners
A1 is the starting level of the CEFR framework — the entry point into English. At A1 you can introduce yourself, ask and answer simple personal questions, recognise common signs and instructions, and have short slow-paced conversations on very familiar topics.
Grammatically, A1 covers the building blocks: present-tense forms of be, have, and do; basic word order; simple questions; and the most common determiners, pronouns, and prepositions. Knowing your level matters — A1 material teaches the foundations every later level builds on, while a B1 textbook will overwhelm you. Start here and progress is fast.
Difficulty: Easy
The Easy difficulty tag marks questions and challenges aimed at beginners — typically A1 or early A2 level. Expect single-rule focus, short sentences, common everyday vocabulary, and one clear correct answer. Distractors usually rule themselves out quickly.
Filter by Easy when you're rebuilding fundamentals, warming up before harder material, or testing whether you've truly internalised a basic rule before moving on. Easy doesn't mean trivial — it means the rule itself is unambiguous and the context doesn't pile on extra complications.