They ______ playing football this afternoon. （   ）

A．is

B．am

C．are

Choose, think and write.
be going to/ should
1. You ______ clean your room now.
2. They ______ visit the museum tomorrow.
3. She ______ have a swim next Sunday.
4. You ______ be late again.
5. Children ______ eat too many hamburgers.

The pen ________ on the desk.

A．am

B．is

C．are

My legs short. （  ）

A．am

B．is

C．are

用所给词的正确形式填空。
【小题1】We should stop _________ (throw) rubbish into rivers.
【小题2】In the past, the Earth _________ (be) clean and beautiful.
【小题3】My brother is __________ (plant) trees in the backyard.
【小题4】The Earth __________(get) sick now.
【小题5】We shouldn’t __________ (cut) down so many trees.