题目内容:
Theauthor'spurposeinpresentingthefirstparagraphis
A.toexplainthebackgroundandnewfeaturesoftoday'sastronomy. B.todiscussindetailthemostrecentachievementsinspaceresearch.
C.tointroducesomenewlyestablishedspacestations.
D.toillustratethattheworldtodayisdifferentinmanyaspectsfromthatofagenera-tionsago.
参考答案:
答案解析: