II . Complete the sentence according to the picture（根据图片提示，完成句子）

【小题1】We are good friends. We always help each ____________.
【小题2】PM 2. 5 is now being used to monitor the air ____________ in the cities.
【小题3】Don't throw away those bags. We can ____________them.
【小题4】The boys likes playing _____________.
【小题5】We are going to visit the ____________ this winter holiday.