是but,except前有实义动词“do”时,后可跟不带to的不定式.如无“do”,则要带.即有do无to,无do有to. 例子：The animy can do nothing but/except surrender(投降).The animy had nothing to choose but/except to surrender.另外这里有些特殊的固定搭配：1.had better/best （not）do sth 最好（不)做某事2.would/had rather（sooner）do sth+than sth；would/had soon do sth+as do sth宁愿做某事而不愿做某事3.cannot but/cannot choose but/cannot help but+do不得不做某事4.do nothing (not do anything)but/except+do sth只能做某事.