1 . The mixture of better jobs and greater chances of self-promotion is _____ lies behind the return of oversea Chinese high-tech talents.

A．why	B．where
C．what	D．when

2 . I don’t really mind you allowing Tom to leave the company at this key moment. The problem is _____ can be sent to replace him.

A．what	B．who
C．that	D．which

3 . —When choosing clothes, you focus on the price while I think more about the design.
—That’s _____ we are different from each other.

A．how	B．what
C．which	D．where

4 . I went out to take part in a party with my friends and didn’t come home until midnight last night. That’s _____ my mother got so angry with me.

A．what	B．how
C．when	D．why

5 . The reason ___ __his being late for the meeting was ___ __his little son fell ill this morning.

A．for … that	B．why … that
C．for … because	D．why … because