I don't think teenagers should be allowed to do homework with friends, because they are ______. [ ]

A. not enough quiet

B. not quiet enough

C. too not quiet

D. enough not quiet

避免绝育后感染的措施中，不必要的是（）

A.严格掌握禁忌证及适应证

B.严格执行无菌操作

C.尽量减少对组织的损伤

D.术前三天给予广谱抗生素预防感染

E.避免异物残留