In the mid-1970’s, since birds were overcome by pollution, and routinely falling from the sky above Los Angeles freeways, this prompted officials in California to devise a plan that reduced automobile emissions.
A. since birds were overcome by pollution, and routinely falling from the sky above Los Angeles freeways, this prompted officials in California to devise a plan that reduced
B. since birds that had been overcome by pollution were routinely falling from the sky above Los Angeles freeways, it prompted officials in California to devise a plan that would reduce
C. birds had been overcome by pollution and routinely fell from the sky above Los Angeles freeways, prompting officials in California to devise a plan that reduced
D. birds overcome by pollution routinely fell from the sky above Los Angeles freeways, prompting officials in California to devise a plan to reduce
E. birds overcome by pollution and routinely falling from the sky above Los Angeles freeways were prompting officials in California to devise a plan to reduce
In generally, use simple past tense if possible. For
instance, you will say,
"Yesterday, I found out that Dinosaurs lived on Earth for 3
million years" (sorry that I made up the number....)
Use past perfect tense ONLY if you need to emphasis the
sequence of the action.
"Yesterday, I found out that Dinosaurs had lived on Earth
for 3 million years before they died out."
Here, you wanna to emphasize the sequence of two actions,
namely "had lived" and "died out."
In the absence of other better choices, you may use "had".作者: finnlijing 时间: 2011-12-22 21:04
但是此题overcome by pollution 和 fell from the sky 不是也应该有先后关系么？应该是先overcome...,再 fell from the sky. 所以觉得正是应该用完成时态来表示这个时间的先后性呀。作者: vansonkated 时间: 2011-12-27 06:45
