The cruel mother________at the poor daughter repeatedly with a stick because she didn't do well in her studies. A.beat B.hit C.struck D.knocked 答案:C四个选项中,beat指连续敲打,hit指击中,两个词都常作及物动词;knock at是“敲打”的意思,根据该句的语境,用木棍打某人,应该用strike。
水在生物体的许多化学反应中充当:
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A.
溶剂
B.
催化剂
C.
载体
D.
还原剂