used to do sth.造句

1、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.(既不是陳述事實也不是描寫狀態(tài)，無法證實，但被說話者用來做事的。)

2、Sth . beused to do sth.(是固定詞組，意思是用來做某事。)