当前位置:首页 >> 英语六级词汇

有关know的两个特殊结构

发表时间:2006年12月28日 来源:四六级考试网

有这样两道CET-6题:
(1)You should know ________ to go swimming right after meals.(A.more than B.better than C.rather than D.other than)
(2)I 've never known anyone _______such a hot temper as your father.(A.has B.had C.to have D.having)
上列两题均涉及到常用动词know的两个特殊结构:know better than to do sth.和 know sb.to do sth./do sth.这两种句型常出现在大学英语教材之中。

(一)know better than to do sth.的英文解释是be wise or experienced enough to avoid making mistakes,其意为"很懂得不该去做某事"、"明事理而不至于做某事"、"具有充分智慧或经验而不去做某事"、"不会愚蠢(糊涂)到去做某事"。这个结构隐含否定意义。例如:
(1)You should know better than to go out without an overcoat on such a cold day.你 应该知道在这样冷的天气出门而不穿大衣是不行的。
(2)I knew better than to quarrel with her.我不会糊涂到跟她吵架去。
(3)He ought to have known better to run away from school.他逃学了,他本应该懂得不该这样做的。
know better一般被认为是know better than to do sth.的省略形式,虽然其后没跟任何句子成分,但仍具有否定意义。它作为一种委婉的说法,多用于口语中。例如:
(4)Can't you know better!你就不能学乖点儿吗?
(5)He told me he had never been to a gambling house,but I knew better.他告诉我他从没进过赌场,可我不相信。

(二)在know sb.to do sth./do sth.句型中,当know为完成时或过去时态时,不定式复合结构可带to,也可不带to。例如:

(6)They didn't know John(to)give better speeches than that of last week.他们不知道约翰发表过比上周更好的演说。

(7)I have never known a man(to)die of love,but I have known a disappointed lover(to)lose weight.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。
但在下列条件下,只能用know sb.to do sth.结构,也就是说,不定式符号to不能省略。

1.know为一般现在时。例如:
(8)We know him to be a coward.我们知道他是个胆小鬼。

2.know为完成时或过去时态,但不定式是be式或be的完成时。例如:
(9)The hostages have hardly known the chances of release to be slim .这些人质几乎不知道他们获释的机会渺茫。
(10)They knew them selves to have been in a difficult position.他们知道他们的处境很难。

3.know用于被动语态中。例如:
(11)He is known to be a young man with lofty ideals.人们都知道他是一个有抱负的青年。
(12)Bob was known to have had a quick temper as a boy.人们都知道鲍勃在孩提时代脾气暴躁。