Being a teacher can't be easy. (MUST) --> Being a teacher _____________________ .

There's no need to carry a passport to travel to another country in Europe. (NEED) --> You ____________________ a passport to travel to another country in Europe.

My friend was late to Biology class, so we couldn't present our project on the life cycle of silkworms. (ABLE) --> My friend was late to Biology class, so we _____________________ our project on the life cycle of silkworms.

You didn't ask me for help. I could have helped you! (SHOULD) --> You _____________________ me for help!

The use of mobile phones is prohibited in our classroom. (ALLOWED) --> Students ____________________ use mobile phones in our classroom.

If we don't leave now, we'll miss the bus. (HAD) --> We ____________________ now or we'll miss the bus.

Oh, no. Do not let the dog in my sister's bedroom. She'll get angry! (BETTER) --> You ____________________ let the dog in my sister's bedroom.