例如：
They supposed the paper to have been lost during the war. 他們認為那個文件在戰(zhàn)爭期間丟失了。
The police arrested him because he was supposed to have killed the lady. 警察逮捕了他，認為他殺死了那位女士。
suppose 可用于“ be supposed +不定式”的結構。
be supposed to do sth. = should do sth. 意為“應該 / 理應做某事”，表示被期望或被要求(按規(guī)則、慣例)做某事。
例如：
We are supposed to help each other. 我們理應互相幫助。(要求)
You are supposed to hand in your papers before class is over. 希望你下課前交卷子。(期望)