Questions of Princeton 2

6.Ornithologists find it difficult to study the Amazonian Biffa, a species native to the Amazon watershed, mainly on account of its feeding and nesting at great height often 200 to 300 feet above the forest floor.

a. on account of its feeding and nesting

b. on account of their feeding and nesting

c. because it feeds and nests

d. because they feed and nest

e. because of their feeding and nesting

The answer is C. But why choose C?

题目前面已经有一个it指代to study the Amazonian Biffa，而选项C的it指代the Amazonian Biffa，是否造成指代不清？

29.A grasshopper is larger than normal for a member of the insect class; its abdomen can be up to two inches in length, as opposed to the one-inch-long abdomen of the average insect.

a.normal

b. is normal

c. was normal

d. they normally are

e they are normally

The answer is B. I'm confused about the difference between a and b.

17.The capacity to follow instructions of a parallel processor is not limited by the speed at which its components can operate but by its ability to integrate the work of each component.

a. The capacity to follow instructions of a parallel processor is not limited by

b.The capacity to follow instructions in a parallel processor is not limited to

c.The capacity to follow instructions in a parallel processor are not limited to

d. A parallel processor's capacity to follow instructions are not limited by

e. A parallel processor's capacity to follow instructions is not limited by

The answer is A. 我选A，无生命的所有格不是要用of？