ⅷ、过去完成时
由"had+过去分词"构成该时态的谓语,各人称都一样。
表示在过去某一时刻或动作之前已经完成的动作,这个表示到过去某一时刻为止的时间状语常用by, before等介词或连词引导的短语或从句来表示。
e.g. by the end of july last year, i had worked （工作）for forty years.
注意：
e.g. i was told(告诉) that（银行） had been robbed（抢劫）. the bank
含有after, as soon as, before等连词引导的状语从句的复合句中，由于连词本身已明确动作发生的次序,所以,这个从句也可以用一般过去时表示，不用过去完成时。如：
e.g. students went out after（响）. 铃响后同学们出去了 the bell rang
e.g. i informed him of the progress of the work as soon as i arrived here
我一到这里就把工作进程告诉了他。
练习与体会：
（综合c级：the cherokee nation）
the cherokees refused（拒绝） to go（离去）. they had lived （生活）on their lands for centuries.
when the last group arrived in(到达) their new home（家园） in march 1839, more than 4,000 had died（死）.
提示:相临句子之间的时态关系在解题中的巧妙运用
2005年职称英语卫生类／综合类c补全短文考题:
from caribbean islands加勒比海海岛
(第3段) the caribbean islands form a chain that（岛屿） were formed by the eruption (爆发) of ancient（古代的） volcanoes (火山). ___(46)__. separates the caribbean sea from the rest of the atlantic ocean. some of the islands
a. but life on the caribbean islands is not always painful.
b. the earliest name used by europeans is the indies
c. others are low-lying coral islands that gradually rose from the ocean.
d. they are cuba, puerto rico, jamaica, and hispaniola
e. many tourists arrive on cruise ships.
f. there are countless small islands to bury treasure（财宝） or hide（兽皮） on
46. c。 分析: 利用时态作为直接的答案线索.空格前句使用的是一般过去时态, 根据文章中前后句使用时态通常一致(除非句子中带有特别的时间状语), 所以推测空格处的句子时态很可能也是一般过去时态, 或过去时态的某一种. 因为判断只有c最可能是答案(只有c中出现了过去时态的结构). 空格前面出现了代词some(some指“一些岛屿”)， some往往和 others形成一种呼应结构， 而c中就出现了others， 而且c中的others也是指“岛屿”，因此肯定了c是答案。