It is uncertain ________ side effect the medicine will bring about, although about two thousand patients have taken it.
| A．that | B．what | C．how | D．whether |
It was until dark ___ he found ___ he thought was the correct way to solve the problem.
| A．that; what | B．that; that | C．when; what | D．when; that |
It was in the evening__we reached the littletown of Winchester.
A that B. untilC. sinceD. before
.It was ____ my teacher worked ____ I work hard.
| A．where; that | B．where； where | C．that; that | D．that ;where |
It is the young man ___ looked for ___ caught the murderer.
A.that; who B.that; theyC. they ;thatD they ;which
It is on a winter night ___he spent with me last night.
| A．that | B．where | C．as | D．when |