高中英语 知识点大全29 but的用法

高中英语知识点大全（29）：but的用法1、broadcastbroadcast vt.;vi.广播;播放。过去式和过去分词均为broadcast。The BBC broadcasts every day.BBC每天都广播。The news was broadcast on the radio.这个消息是收音机里播送的。2、butbut  prep. 除之外。与except同义，除了的部分与其他部分不在一个范围内，不具有一致性。except适用场合较多，but 主要用于带有nothing/nobody/no one/all 等不定代词的句子。No one except/but you was late.除你之外没有迟到。（你迟到了）We all went to see a film yesterday evening except/but you.除你之外作天晚上我们都去看电影了。（你没去）That window is open except in winter .除冬天外那窗户一直开着。（冬天不开）另外，but后可接不不定式。如果句子前面有实义动词do及其变化形式时，不定式不带to; 否则不定式带to .I did nothing yesterday evening but watch TV.昨天晚上除看电视外我什么也没干。He had no choice but to leave.他只得离开。注意：besides 也是介词，意为“除之外（还有）”。除了的部分和其他部分在同一个范围内，具有一致性。We all went to see a film yesterday evening besides you.除你之外昨天晚上我们也都去看电影了。（你和我们都去了）Who is going there with Tom besides you? 除你之外还有谁和汤姆一起去？3、but for该短语介词意为“要不是”，后接名词（=without + n.）,but for短语相当于一个虚拟条件句，因此，句中谓语动词用虚拟语气。如：The boy would have drowned but for your help.如果接的是句子，but for要换用成but that如：He would have helped us but that he was short of money at the time.(= if it had not been the fact that he was)