With the successful launch of Tiangong-l, which was breakthrough in space field,China's space dream took a step closer to reality.
A. a;/
B. the； a
C. a; the
D. the;/
网友回答
(答案→)A. a;/
B. the； a
C. a; the
D. the;/
解析：考查冠词。可数名词单数前加a/an；表泛指，意为“一个”；the是特指，意为“那个，这个”；不可数名词前不用冠词。breakthrough突破，这里是指“天宫一号”的成功发射，是具体的一件事，前用不定冠词a；排除B、D；reality现实，不可数，排除C。故选A。