As time went on, people came to be of the seriousness of China's population.
A. aware
B. abundant
C. adequate
D. alarmed
网友回答
(答案→)A. aware
B. abundant
C. adequate
D. alarmed
解析：考查形容词。A意识到；B大量的；足够的；D惊恐的。这里考查短语be aware of意识到。句意：随着时间的推移，人们开始意识到中国人口的严重性。故A正确。