The students stopped ________ when the teacher came in.

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When the teacher came in, the students stopped _______ and became very ________.

A. to talk, quiet?????? ????????????? B. talking, quiet????????????? C. to talk, quietly????????????? D. talking, quietly

When the teacher came in, the students______ at once.

A．stopped to talk                         B．stopped talking

C．stoped talking                          D．stoped to talk