Here are the correct options for each sentence:
- You b) mustn't cross the road here. It's very dangerous!
- Ann is always ready to take part in school activities. She is very a) enthusiastic.
- What are you looking a) for? - I can't find my glasses.
- His parents want him b) to stay out of trouble.
- If we b) try we may win.
- I b) must come to school early in the morning.