The teacher, along with his students, _____ experiments in the laboratory when the explosion happened.

[     ]

A. were doing
B. have been doing
C. was doing
D. had done
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科目：高中英語 來源： 題型：

.The teache rfound ____ difficult to decide____ he would take with him to attend the

conference.

  A.it;whom        B.himself;who       C.this;whom      D.that;who

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