在高考语法中，非限制性定语从句容易和别的句型相混淆，为此，小编特为广大考生推出该专题，希望对大家有质的帮助！

请看下面一题，是考查非限制性定语从句吗?

If the man is only interested in your looks, _____ just shows how shallow he is.

A. as B. which

C. what D. that

【分析】容易误选A或B，误这是非限制性定语从句。正确答案为D，注意逗号前是一个条件状语从句，逗号后是该状语从句的主句，that 在此代表前文所述的情况，用作主句的主语。类似地，下面几道题也选 that，而不选 which：

(1) If you promise to go with us, _____ will be OK.

A. as B. which

C. and it D. that

(2) If you want a double room, _____ will cost another ￡15.

A. as B. which

C. what D. that

(3) Whether you go or not, _______ is quite all right with me.

A. that B. which

C. and it D. so

(4) When I say two hours, _____ includes time for eating.

A. as B. which

C. what D. that