Of the two brothers, Bill is ___ younger one, and he is ____ quiet boy, one that most adults like very much.
| A．the; a | B．a ; the | C．a; one | D．the ; the |
_____ I admit that the problems are difficult , I don’t agree that they cannot be solved.
| A．While | B．Suppose | C．Because | D．as though |
It was found that although the girl could perceive things with her fingers, this ability ceased _____ her hands were wet.
| A．the moment when | B．the moment | C．in that moment | D．before |
______ you understand this rule, you’ll have no further difficulty.
| A．while | B．Once | C．Though | D．Unless |
It will not be long _____man can harness the solar energy and make it serve mankind.
| A．since | B．before | C．when | D．after |
Doing your homework is a sure way to improve your test scores, and this is especially true______ it comes to the classroom tests.
| A．before | B．as | C．since | D．when |