Question

【题目】________a teacher has given permission is a student allowed to enter the classroom.

A. If only B. Only if

C. As if D. Even if

Answer 1

【答案】B

【解析】考查状语从句。if only意为“只要，若要……就好了”；as if意为“好像”；even if意为“即使”；only if意为“只有”，通常位于句首。从句意和句子的结构可知本题正确答案为B。