椎骨为人体的不规则骨。
参考答案：对
---This is Jane speaking.
----Oh, it’s you.Your voice sounds quite different ___ the phone.
A．for
B．from
C．by
D．on
A．mgtgθ
B．mgsinθ
C．μmg
D．μmg
mgtgθ
mgsinθ