fall by和fall to区别

下降的多少不同fall by意思是下降了多少，后面一般接数值或百分数。 fall to意思是下降到多少，后面一般接数值。fall to 4.7 percent意思是下降到了百分之四点七而fall by 4.7 percent则是表示下降了4.7个百分点

1、侧重点不同

（1）fall by侧重点在于下降了多少、变化的数量。

例如：Shareholders have seen the value of their shares fall by one fifth since last july。

翻译：股东们看到了他们的股票价值从去年七月以来下跌了五分之一。

（2）fall to侧重点在下降后的数值，后面一般接数值。

例如：BlackBerry has seen its share of that market fall to 7% from 34% two years ago。

翻译：黑莓的市场份额则从两年前的34%降到了现在的7%。

2、后面接的内容不同

（1）fall by后面除了接数值还可以接百分数。

（2）fall to后面一般接数值。

fall用作连系动词只限于和少数形容词或名词搭配。

1、 fall asleep

The child soon fell asleep.

孩子很快睡着了。

While he was studying， he fell asleep.

他念书念得睡着了。

He fell asleep with the light still burning.

灯还开着他睡着了。

He said that if he fell asleep at the wheel she was to wake him up.

他说，如果他在开车时打瞌睡，她必须把他叫醒。

2、 fall ill

Tom suddenly fell ill yesterday.

汤姆昨天突然病了。

He has fallen ill.

他病了。

He was to have been the new ambassador， but he fell ill.

他本来要出任新大使，但是病倒了。

3、 fall silent

He fell silent.

他静了下来。

At the President’s entry everyone fell silent.

总统进来时大家都安静下来。

4、 fall a victim

He fell a victim to her charms.

他成了她魅力的受害者。

Lots of people fell victims to fascism.

许多人成了法西斯的受害人。

5、 fall prey

The zebra fell prey to the lion.

那斑马被狮子捕食。

She was prey to irrational fears.

她遭受着无端恐惧的折磨。