業精於勤，事立於豫

兩個動詞同時：兩者皆用簡單式

兩個動詞不同時：先完成用完成式，後完成用簡單式。

Note:兩個動作不同時「時間差」,一動作用簡單式,另一動作用完成式。

實例講解

1. He remembered a kind of glue developed by a colleague that everyone thought _____ a failure because it did not stick very well.

(他記得他的同事曾經開發過一種膠水,然而每個人都認為那個發明是失敗的,原因在於此種膠水的黏著力不佳。)

(A) is

(B) was

(C) will be

(D) has been

Ans: (B)

所有的動作皆在敘述一個過去的事實，故答案選(B) 。

2. Before he was elected to the Prussian Academy of Science, Alben Einstein _____ as an examiner at the Swiss Patent Office in Bern.

(愛因斯坦在進入普魯士科學院之前,曾經是個任職於伯恩的瑞士專利局的檢驗員。)

(A) serving

(B) had served

(C) has served

(D) senves

Ans：(B)

after / before有「時間差」的概念,一動作用簡單式,另外一動作用完成式;句中的was elected用過去式,另一動作用過去完成式had served。

3 After James _____ for fifteen minutes, he began to feel tied.

(詹姆士在慢跑十五分鐘之後感到疲倦。)

(A) has been jogging

(B) jogging

(C) has jogged

(D) had been jogging

Ans：(D)

after/ before有「時間差」的概念,一動作用簡單式,另外一動作用完成式;句中began為過去式,另外一動作用過去完成(進行)式had beenjogging。

Note :完成進行式,強調該動作的進行。

4. By the time the police came, _____. 

(警察趕到現場之前，現場已聚集大批群眾。)

(A) the houses were burning

(B) the firefighters have put out the fire

(C) an ambulance took the man to the hospital

(D) a large crowd of people had gathered

Ans:(D)

by the time = before ,含有「時間差」的概念,一動作用過去式came ,另外一動作用過去完成式had gathered。

5. We can only hope that the MRT _____ before we move to our new location.

(我們只希望在搬到新地點前，捷運可以通車。)

(A) will finish

(B) will have been finished

(C) was finished

(D) finish

Ans： (B)

after / before含有「時間差」的概念,一動作用簡單式,另一動作用完成式;句中move為現在式(表時間的副詞子句不加will ,故在此類型的副詞子句中,現在式 = 未來式) ,另外一動作用未來完成式。