_______ is certain, people’s living conditions in China have improved a lot since the 1980s.

A. It                   B. As       C. what             D. Which

By serving others, a person focuses on someone other than himself or herself , _____ can be very eye-opening and rewarding

A. who           B. which             C. what       D. that

With the development of agriculture, the people _____ village I taught before have lived a happy life.

A. who           B. whose              C. in whose    D. in which

Yesterday he sold out all his stamps at _____ he thought was a reasonable price.

      A. that          B. which           C. what       D. as

The reason ______ he gave for not coming was ______ his mother wouldn’t allow him to.

      A. why ; that     B. for which ; that    C. why ; because   D. which; that

Have you asked her for the reason _______ may explain her absence from class last week?

     A. why                           B. that                      C. what                     D. for which

______ is expected, according to the online survey, is _______ prices of houses

   will not go up an more.

  A. What; that       B. As, that       C. It, what       D. Which, that

To my mind, she is the most wonderful teacher that I’ve ever known, _______ is able to get across to her students ______ she really thinks and means.

A. which; that        B. that; as        C. who; what      D. who; that

________one scientist has pointed out, children’s skulls are not fully developed.

A. That                 B. As                    C. Which               D. What

—The guard keeps         watch at the gate.

 —So he does. Only those         knows well could be let in.

A. close; who      B. tight; whom     C. tight; that        D. close; he