单选题 The reason why NASA hopes to carry out at least two moon missions a year starting in 2018 is to ______.

A、 ensure the moon traveling and the moon base construction
B、 speed up the moon base construction and other activities
C、 guarantee the quality of the researchers' scientific study
D、 set up new training laboratories for future missions to Mars

【正确答案】 B

【答案解析】[注释] 按照一般阅读理解题的顺序，最后一道题可以在文章的最后部分找到依据句。本题的依据句为文章的最后一句话：This will allow for quick moon base construction， constant scientific Study，and training for future missions to Mars．依据句中的allow for quick与B项选择中的speed up相对应。其他选择项都没有涉及，属于无关信息。