---Tell us, Mark, what is the cause of the American Civil War?
---Well, is it _______the black slaves wanted freedom?
| A．how | B．why |
| C．because | D．when |
We should produce less things from raw materials, _____ is growing smaller and smaller.
| A．whose supplies | B．the supply of which |
| C．which supply | D．the supply of whom |
As fuel prices rose, bus companies raised their fares and _____.
| A．so did the airlines |
| B．nor did the airlines |
| C．so the airlines did |
| D．nor the airlines did |
Friendships between girls are usually ________ shared feelings and support, but friendships between boys are based on shared activities or interests.
| A．cautious about | B．absorbed in |
| C．anchored in | D．concerned about |
---Isn’t it time you went to bed, Mike?
---I _____ painting all afternoon, so I have to finish my homework now.
| A．have been practicing | B．have practiced |
| C．was practicing | D．had practiced |
______ is no debating that the Dallas Mavericks will defeat the Washington Wizards in the next game.
| A．It | B．As | C．That | D．There |