Ⅰ.牛刀小试:指出下列各句中划线部分是什么动词，并说明词义。
例如：All of us study hard.（vi. 学习）
He began to work at seven this morning.（       ）
I have left the key at home.（        ）
We must take the old woman to the hospital at once.（       ）
Billy felt very sad when he heard the bad news.（        ）
Think it over, and you will have a good idea.（         ）
Don’t think of yourself；think of others.（                 ）
We are college students now, but we were at the factory two years ago（    ）
Mr. Black got angry when he saw Jenny come to school late again.（          ）
Please wash your hands before each meal.（         ）
Li Ming often works for the wall-newspaper after school.（           ）