题目内容：

选A还是B,求准确答案,资料上是A老师说是B~求高手解答,详细一些~
Children under sixteen are not permitted to participate in such kind of activities _____ bad for their
mental development.[ ]A. as is
B. as are
C. that are
D. that they are

优质解答

A
首先,这儿考查的是as引导的定语从句.其次,与kind有关的词组都遵循就前原则,如 a kind of books 即用动词的单数形式,而bread of kinds也用动词的单数形式