三、平行结构
技巧：如果填空题中空格的后面有and, 或者and后面有空格，那么这道题目一定是考察平行结构。填空题中平行结构出现的形式是： A and B, A , B, and C
例1：The technique of recording, classifying, and___is known as accounting.
(A) an enterprise's transactions summary (B) the summarizing of an enterprise's transactions
(C) transactions of an enterprise are summarized (D) summarizing the transactions of an enterprise
分析：空格的后面是and, 一般考平行结构，空格处缺与前面recording、classifying并列的动名词。四个选项中只有（D）符合条件，故选（D）。
例2：Louis T. Wright, a surgeon, developed ingenious orthopedic braces, ___, and supervised the first use of Aureomycin on human patients.
(A) treating skull fractures that he pioneered in (B) pioneered in treating skull fractures
(C) which pioneered in treating skull fractures (D) he was a pioneer in the treatment of skull fractures
分析：空格后面是and, 空格处缺少和developed、supervised平行的谓语动词，因此选择（B）。