单项选择题

For years, astronomers struggled to calculate the age of the universe.

A．多年以来，宇航员们在努力计算宇宙存在的时间。
B．多年以来，宇航员们在努力地探索，力求揭开宇宙的年龄之谜。
C．多年以来，宇航员们在挣扎地探索，力求揭开宇宙的年龄之谜。
D．多年以来，宇航员们在努力地计算宇宙的年龄现象。
<上一题 目录 下一题>
热门 试题

单项选择题
There are few places in this country ______ wheat can't grow well.
A．where
B．which
C．when
D．if
单项选择题
John said that he ______ London twice.
A．have been to
B．have gone to
C．had gone to
D．had been to
相关试题