问题
选择题
_______ in the school rules that boy students should not wear long hair.
A．What is required
B．What requires
C．It is required
D．It requires
答案
答案：C
考查名词性从句。it是形式主语，that引导的从句是真正的主语。
搜题请搜索小程序“爱下问搜题”
=97%，
=0.3%，
=0.7%，
=2%，则标准状态下的平均黏度为（）[各组分的运动黏度(10-6m2/s)为：CH4=14.5， C3H8＝3.81，C4H10=2.53，N2=13.3]。