在动词 know 的过去时 knew 和完成时 have/had known 后面,不定式作宾语补语时,不定式可以带 to 也可不带 to。例如:
I never knew him (to) act without thinking. 我从未见他轻率行事过。
I’ve never known her (to) be late before. 我以前从不知道她迟到过。
I’ve never known him (to) pay for a drink. 我从来没见他付过酒钱。
I’ve never known it (to) rain like this. 我从没见过这样下雨。
I’ve never known it (to) snow in July before. 我以前从未见到过七月份下雪。
偶尔也会出现在一般现在时的know后面接的作宾补的不定式不带to的情况,但非常少见。