Q41:

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

1. to be huge reservoirs of energy, possibly causing sea floor instability, and
2. to be huge reservoirs of energy, possibly causing sea floor instability, and even as
3. as huge reservoirs of energy, possibly causing sea floor instability, and
4. as huge reservoirs of energy, and the possible cause of sea floor instability,
5. as huge reservoirs of energy, as possible causes of sea floor instability, and even as

Answer: A

mine:e

我觉得e是一个很好的并列结构:be studied for their potential as 1,as 2, and even as 3.

possibly causing sea floor instability是有歧意的,

即可能修饰主语gas hydrate,或者修饰最近的名词energy

而且按照e这么理解,并没有不可以的.