Millions of people watched the Chang'e-l satellite flying around the moon on TV,＿＿how difficult
问题描述：
Millions of people watched the Chang'e-l satellite flying around the moon on TV,＿＿how difficult
and dangerous an advanture it is.
A.aware of B.aware thatC.awaringD.and awared E.awaring of
请说明原因
答
B== Millions of people watched the Chang'e-l satellite flying around the moon on TV.They were (well) aware (of) how difficult a time the Chinese scientists had getting it into operation.