过去常做某事

be supposed to do sth───应该做某事；被期望干某事

fed to death───感到厌烦死了

have got to do sth───不得不做某事

have to do with───与…有关

not one to do sth───不做某事的人

put a stop to sth───制止某事

take care to do sth───注意做某事

bored to death───令人厌烦得要死

have/be to do with───与…有关

Perfomatives: are the sentences that did not state a fact or describe a state, and are not verifiable. But they are used by the speaker to do STH.───不是陈述事实也不是描写状态，无法证实，但被说话者用来做事的。

Sth . be used to do sth.───是固定词组，意思是用来做某事。

Describing a repeated act or habit of the past, which is no longer true now: used to do sth.───描述过去重复的现在不再有的动作或习惯

be used to do sth. = be used for doing sth.───被用来做某事

We always mix it up with be used doing sht or be used to do sth.───我们老是会将它与习惯做某事、被用来做某事这两个短语混淆

he looks old than his age. When i was young, he used to tell me the importance of study. used to do sth───过去常常做某事的意思，符合本句的意思，本句是他看起来比实际年龄要老。当我小的时候，他常常告诉我学习的重要性

used to do sth stand for───过去常常做某事代表，象征

A pen is used writing. be used to do sth───被用来去做某事如