_______isknowntoall，Chinawillbean_______powerfulcountryin20or30years’time.
C
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。
句子写作：The judge had a hard time deciding___________________.
句子写作：Today at school Mr Moore brought in his pet rabbit. He showed it to the class.
在发生人感染H7N9禽流感确诊病例的县(区)内，应当在病例确诊后开展为期()的强化监测
句子写作：Mypresentationseemedtogowell.
句子写作：”Happy Christmas “he said.