_______ is known to all，China will be an _______ powerful country in 20 or 30 years’ time.
A、That；advancingC
as可以用来引导一个非限制性定语从句，通常无明显的先行词。as指代的是主句陈述的内容。而as引导的从句既可以放于句首，也可以放于句末或句中。
Your firm has been recommended to us by the James Olivier & Co. ____ we have done business for many years
We note from your letter of September 10th that you are interested ____ walnut meat.
The missing boys were last seen ________ near the river.
It is difficult to understand this kind of _______ calculation.
We are glad to receive your telegraphic order of May 6, ______ regret that we can not supply the goods ______ the end of May.
