船不得不返航。

2.reduce vt.& vi.减少；降低；缩小

Breathing exercises can help reduce stress.(教材P10)

有氧练习能够帮助减少压力。

reduce speed　减速

reduce costs 降低成本

reduce expenses 缩减费用

①The factory makes every effort to seek its profit and reduce__costs.

那家工厂竭尽全力去追求利润，降低成本。

②Joe had to reduce__his__speed on the highway for the sake of an unexpected rain.

由于一场不期而至的雨水的缘故，乔不得不在高速公路上减慢了车速。

[辨析比较]　reduce...to/reduce...by

reduce...to 表示"减少到......"；其中介词to表示"减少后的结果" reduce...by 表示"减少了......"；其中介词by表示"程度或幅度" [图形助记]

[名师点津]　reduce的近义词是decrease，反义词是increase。这三个词的用法相似：后可接to(表示增减的结果)和by(表示增减的幅度)。

③Their salary has been increased by 20 percent since last year.自去年以来，他们的工资已经增长了20%。

3.prefer vt.更喜欢，宁愿

I prefer listening to music.(教材P11)

我更喜欢听音乐。

(1)prefer doing/to do sth　更喜欢做某事

prefer sth to sth 喜欢某物胜过某物

prefer sb to do sth 宁愿某人做某事

(2)prefer doing...to doing...＝prefer to do...rather than do... 宁愿做......而不愿

做......