[求助] 大全401

cmclgmet

1.        In terms of physics, the characteristic feature of the roller coaster is that the cars’ potential energy, gained through their being lifted by a chain drive through the Earth’s gravity to the top of the first drop, has been converted to kinetic energy by the time the ride ends.

(A) cars’ potential energy, gained through their being lifted by a chain drive

(B) cars’ potential energy, a gain achieved as they are lifted by a chain drive

(C) potential energy from the cars’ being lifted by a chain drive

(D) potential energy of the cars, gained as a chain drive lifts them（D）

(E) potential energy gained by the cars, being achieved while a chain drive lifts them

请问has been converted 用现在完成时, lifts是不是该用过去时呀

[此贴子已经被作者于2006-11-15 7:22:14编辑过]

cmclgmet

thanks

ypngzhang

1，现在时与过去时不能混用，has been.. 是现在时，所以lift也要用现在时。

2，这里lift是陈述一种客观事实，而不是某一次事件，应该用一般现在时。

我这样解释对吧？

gogirl1981

我觉得这里是有对应的  A has benn converted to B
A：potential energy of the cars 对应B： kinetic energy
A : gained as a chain drive lifts them 对应 B ：by the time the ride ends(as 对应 by the time ,as 在这里表示一个时间的概念)

cmclgmet

ypngzhang ,我觉得lift 发生在 convent 前面,所以用lift过去时,而convent 用现在时.如果lift 用一般现在时.那convent 也应该用一般现在时吧,因为它们说的是一件事呀,

gogirl1981 请问你说的对应是什么意思?