_______Tom is very good at science, his brother is absolutely hopeless.
| A．When | B．While | C．As | D．If |
Jack will hold a meeting ______ people can voice their opinions on today's global economy．
| A．which | B．when |
| C．where | D．whose |
A new learning center has been built in the school, ______ students to get to know the world more easily．
| A．allow | B．allowed |
| C．to allow | D．allowing |
—Something smells really good in here!
—You ______ my Easter cookies．Have one!
| A．smell |
| B．are smelling |
| C．were smelling |
| D．smelt |
—Daddy, how much do you earn an hour?
—If you ______ know, $20 an hour．
A. may B- must
C．can D．should
I ______ for six months．I'm really out of shape．
| A．hadn't exercised |
| B．didn't exercise |
| C．don't exercise |
| D．haven't exercised |