I happened to notice Bob’s father quarrelling with the teacher in defense ofhis son — No wonder Bob always performs poorly in class It’s really “________”

It is accepted by everyone that knowledge is the most valuable _______ for human beings.

The boss had his workers __________________ all day long.

下列对第一课的内容理解不正确的一项是 (　　)

It’s very friendly ______ him tohelp me when I’m in trouble.