题干

Another drug that has helped improve people’s health is penicillin, _________ is _________ by many _________ one of the most important medicines.
A.which, considered, beingB.that, considering, been
C.that, to consider, beingD.which, considered, to be
上一题 下一题 0.4难度 单项选择 更新时间:2013-06-06 10:17:25

答案(点此获取答案解析)