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.

—Here ______ your present, boy. (    )
—Thank you.

A．are

B．is

C．were

Your hair __________ so short then. (   )

A．was

B．is

C．were

There ___a glass of water and three bottles of milk on the table. （  ）

A．am

B．is

C．are

They ______ drinking soya milk. （  ）

A．is

B．am

C．are