当我们从海港起航时，光线逐渐变暗，音乐声逐渐减弱。

(3)His anger faded away.

他的怒气渐渐消失了。

[题组训练1]

完成句子

(1)这颜色会逐渐褪掉的。

The colour little by little.

(2)在这个场景的末尾把音乐逐渐减弱。

the music at the end of the scene.

[归纳拓展2]

"the number of＋可数名词复数"表示"......的数目"，作主语时，谓语动词用单数；"a number of＋可数名词复数"表示"大量的......"，作主语时，谓语动词用复数。

[语境助记2]

(1)The number of smokers，as is reported，has dropped by 17 percent in just one year.(2015·江苏)

据报道，吸烟者的数量仅在一年内就下降了17%。

(2)There are a number of other reasons that might explain why you want to garden.(2016·全国Ⅱ)

有很多其他理由可以解释你想从事园艺的原因。

[题组训练2]

(1)用所给动词的正确形式填空

A large number of students in our school (be) from the countryside；the number

(grow) all these years.

(2)单句改错

The number of students in our school have grown from 1,000 to more than 1,500 till now.

[归纳拓展3]

drop off下降；减少；打盹；顺便把......送到某处

drop out (of...)(从......)辍学；退出；脱离

drop away逐渐下降；减少

drop in (on...)顺便拜访

[语境助记3]

(1)Traffic in the town has dropped off since the bypass opened.

这条旁道通车后，城里来往的车辆就少了。

(2)I'll drop you off on my way home.

我回家路上顺道送你吧。

(3)He had to drop out of the race because of injury.

由于受伤他不得不退出比赛。