I jumped on the train, but it __________ ready.[ ]
A. aren't
B. wasn't
C. isn't
答案:B
眩晕型颈椎病典型的临床症状是()。
A.肩臂麻痛
B.眩晕
C.猝倒
D.行走不稳
E.颈部疼痛
外在水分一般波动较大,直接影响装炉煤的挥发分性能。