原句感知 自主探究 ①I am afraid you have not appreciated the urgency of the matter.

②In the short term, the medicine may not be very effective.

③The job does not require any formal training.

④This kind of fast food is not fit for my appetite.

⑤No horse has a speed comparable to that of his.

⑥I seldom go home after five o'clock in the afternoon. (1)以上例句中黑体部分构成句子的否定形式。

(2)句①③中黑体部分的构成特点是由助动词加_not构成否定。

(3)句②中黑体部分的构成特点是由情态动词加_not构成否定。

(4)句④中黑体部分的构成特点是由系动词加_not构成否定。

(5)句⑤中的 no 和句⑥中的 seldom 本身表示否定意义。 　　[语法剖析]

语法点一 常用否定词 　　1.英语中否定含义的表达形式多种多样，可以用not, no, never, none, nobody, nothing, nowhere等否定词来表达否定之意。

　　We have not signed any agreement.

　　我们没有签署任何协议。

They never have time to go to the cinema during the weekdays.