请教各位NN两到XDF的题目～～谢谢大家啦

1. Gas hydrates, chemical compunds of water and natural gas, are increasingly being studied for their potential to be huge reservoirs of energy, possibly causing sea floor instablity, and significant contributors to global warming.

A   to be huge reservoirs of energy, possibly causing sea floor instablity, and

B   to be huge reservoirs of energy, possibly causing sea floor instablity, and even as

C  as huge reservoirs of energy, possibly causing sea floor instability, and

D  as huge reservoirs of energy, and the possible cause of sea floor instability

E   as huge reservoirs of energy,as possible causes of sea floor instability, and even as

正确答案是A 这里是不是potential to的固定搭配啊

2.Most of Portugal's 250,000 university students boycotted classes in a one-dya strike to protest a law that requires them to contribute $330 a year toward the cost of higher education, previously paying $7 per year.

A   year toward the cost of higher education, previously paying $7 per year.

B   year toward the cost of higher education,  for which was previously paid  $7 per year.

C   year, compared to the previously $7 per year toward the cost of higher education

D  year toward the cost of higher education, instead of the $7 per year required previously

E  year as opposed to the $7 per year required previously for the cost of higher educaiton

正确答案是D

谢谢各位NN了

不晓得 希望有牛牛帮你吧 我也遇到这题目不大会

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