Fill in the blank with the most appropriate modal:
A sign inside the metro coach says: “Passengers ______ lean on the doors. It is not safe.”
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → mustn’t
Complete sentence: A sign inside the metro coach says: “Passengers mustn’t lean on the doors. It is not safe.” The sign says that leaning on the doors is not safe. It tells passengers not to do it.
| Option | Meaning and use | Example |
|---|---|---|
| (1) needn’t | something is not necessary, but it is still allowed | You needn’t bring a pen, as I have a spare one. |
| (2) would | an imagined result in an “if” sentence | If I lived near the sea, I would swim every morning. |
| (3) could | an ability in the past | My grandmother could stitch all her own clothes. |
| (4) mustn’t (answer) | something is not allowed | You mustn’t use your phone inside the exam hall. |