【问】 (A)I have known her to lie.
 (B) I have known her lie.
 请问这两个句子哪个是正确的。
 【答】 这两个句子都是正确的。在know之后使用不带to的动词不定式，仅仅限于英国英语。并且动词know常常采取完成体的形式have known：
 1. I’ve never known anyone have such shining eyes as you.
 我从未看到过有谁有你这样明亮的眼睛。
 2. Have you ever known her lose her temper?
 你看到过她发脾气吗?
 3. I have known John give better speeches than that.
 我知道约翰发表过比这更好的演说。
 4. I’ve never known her to be late before.(LEG)
 我以前从不知道她迟到过。
 5. I have never known a man (to)die of love，but I have known a disappointed lover(to) lose weight. (AED)
 我从未听说过一个人由于恋爱而死，但我却听说过失恋的人会消瘦。
 6. I have never known him make a mistake. (AEG)
 我从未看到过他犯错误。
 但是在被动语态中，know必须跟带to的动词不定式：
 1. He’s known to be a coward. (CGEL)
 人人都知道他是个懦夫。
 2. He was known to be a spy.
 人人都知道他是个间谍。
 3. She is known to lie. (Evans)
 人人都知道她爱说谎。
 4. He was known to have/to have had a quick temper as a boy.(LEG)
 人们都知道他在孩提时代脾气暴躁。
 5. She is known to have the best collection of stamps in the world.(LEG)她以藏有世界上最好的邮票而闻名。