253.Tens of trees were cut down during the night,but no one knew ______.
A.who
B.by whom
C.who to do so
D.who does that
254.The young mother saw her baby fall to the ground,______ brought her heart to her mouth.
A.it
B.and which
C.and that
D.this
253.答案是B;根据句意得知:没人知道树木被谁砍伐。故选B。
254.答案是C;考查代词的指代。此题解题关键是标点符号。C选项and that可改成zwhich引导非限制性定语从
句。
