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标题: 请教doing和by doing的区别 [打印本页]

作者: numero 时间: 2004-8-9 07:47
标题: 请教doing和by doing的区别

究竟什么时候用doing,什么时候用by doing呢?

试举下面一例:

22. Using a Doppler ultrasound device, fetal heartbeats can be detected by the twelfth week of pregnancy.

(E) Using a Doppler ultrasound device, a physician can detect fetal heartbeats by the twelfth week of pregnancy.

答案是E,没问题,但我想问能否在using前面加上by?是否也是正确答案?

作者: perpetual 时间: 2004-8-9 14:19
好像意思上有点不同，请nn来讲讲罢~~~

作者: qianrene 时间: 2007-9-23 22:23
刚查的时候偶然看到，

黄皮OG47.: by providing such services as x, y, and z, and by staying with…., America Bank has become….加不加by都可以

作者: hopelanxyn 时间: 2007-12-12 03:27

以下是引用qianrene在2007-9-23 22:23:00的发言：
刚查的时候偶然看到，

黄皮OG47.: by providing such services as x, y, and z, and by staying with…., America Bank has become….加不加by都可以

我怎摸没有看到说加不加都可以的话???

[此贴子已经被作者于2007-12-12 4:15:11编辑过]

作者: Lilac29 时间: 2007-12-12 09:32
If you want to use "by" before "using", you have to put this phrase in the sentences like the following:

A physician can detect fetal heartbeats by using a Doppler ultrasound device by the twelfth week of pregnancy.

The phrase "using a Doppler ultrasound device" is a prepositinoal phrase that functions as modifier. You cannot put "by" there, otherwise you cannot use comma and you have to put it to the end of sentences.

I think the error of this sentence is dangling modifier.

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