做了套PREP，请教几道语法，欢迎进来讨论~

cindypalau

1. The two oil companies agreed to merge their refining and marketing operations in the Midwest and the West, forming a new company for controlling nearly fifteen percent of the nation’s gasoline sales.
B. forming a new company that would control
E. which formed a new company that would control
（答案是B，但我觉得E是对的）

2. The parachutelike membranes of Africa’s scaly-tailed flying squirrels different from those of the flying squirrels in the family Sciuridae because they are attached to a cartilage rod at the elbow instead of the wrist.
B.because of being attached to a cartilage rod at the elbow rather than at
C.in their attachment to a cartilage rod at the elbow instead of being attached at
D.in that they are attached to a cartilage rod at the elbow rather than at
E.in their being attached to a cartilage rod at the elbow instead of
（答案是D，但我怎么选都是在A,B之间，请问考的是什么语法点？非常不清楚何时用“in that")


3. The Anasazi settlements at Chaco Canyon were built on a spectacular scale with more than 75 carefully engineered structures, of up to 600 rooms each, were connected by a complex regional system of roads.
B. with more than 75 carefully engineered structures, of up to 600 rooms each,
C. of more than 75 carefully engineered structures of up to 600 rooms, each that had been
D. of more than 75 carefully engineered structures of up to 600 rooms and with each(I picked)
E. of more than 75 carefully engineered structures of up to 600 rooms, each had been
(答案是B，是从哪里看出是用with还是of 呢？）

4. Meteor showers and individual streaks of light that flash across the sky every night are generated with tiny flecks of celestial detritus, often no larger than grains of sand or of pebbles, burn up speeding through the atmosphere.
B. grains of sand or pebbles, burn up while speeding
C. grains of sand or pebbles, which burn up while speeding (I picked)   答案是B，我选C，觉得应该用which来修饰前面的pebbles

主要是想了解每到题所考的语法点。多谢各位了~

kaolajiayou

第一题 which指代不清