测定人体重心的方法有()种。
A、2
B、3
C、4
D、5
参考答案:A
What does he think of English Today?
---_______.[ ]
A. He loves it
B. He can see it
C. He doesn't see it
D. That's all right
速度的哪种表示是正确的()。
A、每秒米
B、m/s
C、ms
D、Ms