Fill in the most appropriate modal from the given options.
Measles _____ be quite dangerous.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → can
Complete sentence: Measles can be quite dangerous. The sentence states a general fact about the disease: measles is sometimes quite dangerous, so can is the right modal.
| Option | Meaning and use | Example |
|---|---|---|
| (1) could | past ability or a doubtful, particular possibility ("It could rain later"). A general fact takes can. | As a child, she could swim across the river. |
| (2) can (answer) | Can is used for what is possible in general or what sometimes happens: a general truth. | Mountain roads can be slippery in winter. |
| (3) should | duty or advice. A disease has no duty to be dangerous. | You should see a doctor about that cough. |
| (4) would | Would is used for conditions and polite requests ("It would be dangerous if ..."). Nothing in the sentence calls for it. | I would help you if I had the time. |