__that the demand for power continues to rise at the current rate,it will not be long before~traditional sources become inadequate.A Concerning B Ascertaining C Assuming D Regarding我知道正确答案是C,但这句话的意思我不是特别理解,

问题描述:

__that the demand for power continues to rise at the current rate,it will not be long before~
traditional sources become inadequate.
A Concerning B Ascertaining C Assuming D Regarding
我知道正确答案是C,但这句话的意思我不是特别理解,