大全401，一道好像没有答案的题

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

我觉得D选项也有问题，因为gained分词看起来好像是在修饰紧接着的名词the cars，而不是energy。请高手指教

GMAT语法考的是相对正确。因此即使有缺陷，但是是最优的。

D里面，从逻辑上看，gained是无论如何也不可能修饰cars的。实际上不是特别大的问题。

n1 of n2, which/it ，不像n1's n2, which/it那样，前后两个词可以分开来，利用单复数代词来区别；

即便n1 和 n2 利用同一单复概念，也可以从逻辑意思上来判断，先看一下例子：

OG234：The physical structure of the human eye enables it to sense light of wavelengths up to 0.0005 millimeters; infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long to be registered by the eye

这里it是无争议地指eye，因为它是strucure enables的宾语，同理：

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

这里有个them明确指代cars，而它前面是主语+lifts谓语，所以，如dogdog GG所说：从逻辑上，前面不可能指cars~~

to 携隐

the logic is essential to the modification of SC .