问题
单项选择题
The scientists are()a series of experiments to learn more about how the body adapts to weightlessness.
A.defining
B.having
C.carrying
D.doing
答案
参考答案:D
The scientists are()a series of experiments to learn more about how the body adapts to weightlessness.
A.defining
B.having
C.carrying
D.doing
参考答案:D