The doctor told me to take the medicine .
| A．every fourth hours | B．each fourth hour |
| C．each four hours | D．every four hours |
We’d very much appreciate ___ if you could help us.
| A．this |
| B．that |
| C．it |
| D．you |
—Keep ___ in mind that you have to be here on time.
—OK, I will.
| A．it |
| B．me |
| C．this |
| D．one |
The public ___ of the environmental problem will make the government take it seriously.
| A．existence |
| B．revolution |
| C．awareness |
| D．evidence |
Try on both shoes and walk around to ensure a comfortable fit ___ you know your shoe size.
| A．as if |
| B．unless |
| C．even if |
| D．now that |
I know that ___ would ever discourage him; he would never give up wanting to be a director.
| A．something |
| B．anything |
| C．everything |
| D．nothing |