When the party was over, he ______ his friends good-bye and ______.

Vegetables _____many kinds of vitamins and many other useful materials, so we must eat them______．

I didn’t go outing on National Day because the bad weather ______ the difficulty.

All the people in that town, students or town folks, _______ the books, records and magazines in our university’s library. They can even surf the internet there.

It_____everyone to hear all of the villagers behind the mountain were killed in the earthquake.