The poor ________ living in the mountain ________ top is covered with green trees.                                                     

I, who ______ your close friend, will try my best to help you out of trouble.

 Many a student ________ failed in the biology exam，and Tom is the only one of them who ________ decided to give up the course.

The number of traffic accidents that _______ in developing countries _______ increasing.

The population in our country ____ very ________. 80% of the population ______ farmers.