這個did表強調

請看下面的題：

An awful accident _________, however, occur the other day.

A. does                  B. did                     C. has to                D. had to

【分析】此題正確答案應選B，句末的 the other day 意為“前幾天”，所以句子應用過去時態，而選項D填進去不合題意，故選B。此句有兩個難點：一是句中插有 however 一詞，分散了同學們的注意力；二是所填選項B為許多同學所不熟悉的強調用法。又如(答案均選B)：

(1) Your mother _________, however, say that to us that day.

A. does                  B. did                     C. is doing                D. was doing

(2) Our math teacher _________, however, speak English well.

A. doing                 B. does                   C. is doing                D. was doing