单项填空主要测试考生的基础语法和词汇知识，其考点全面，语境仿真，设题灵活，干扰度大。考生不仅需要扎实的基础知识，还须灵活把握语境，破解干扰项目。单项填空通常从以下角度来设计干扰信息。
A 插入语干扰
He believes in himself, ________in my opinion, is of the most importance.
A. that B. which C. what D. as
B. 标点符号干扰
（1）Tom, ________ sure to come.
(2) Tom ________ sure to come.
A. is B. be C. was D. would
