________ in the regulations that you should not tell other people the password of your e-mail account．

A.What is required

B.What requires

C.It is required

D.It requires

答案及解析： C

解析：

句意为“规定要求你不能告诉别人你的电子邮箱的密码”。此处构成“It is+过去分词+that-clause”句型，其中it为形主语，that从句为真正主语，谓语动词须用被动语态。what不能作形主语，若选A项，题干可改写为What is required in the regulations is that…，这样what从句为主语从句，that从句作表语从句。