Choose the best modal verbs to complete the sentences.

Choose the correct option.

Our teacher says we [mustn't|don't have to] do this homework if we don't want to since it is optional.

[Must|Can] you pass me a pen, please?

Pedestrians [should|must] stop when the light is red.

Don't leave small objects on the ground. Such items [could|should] be swallowed by pets.