风湿性心脏病主动脉瓣狭窄可有()。
A.昏厥
B.脉压小
C.心尖收缩期吹风样杂音
D.主动脉瓣区收缩期杂音伴震颤
E.胸痛
参考答案:A, B, C, D, E
“归纳与比较”是化学学习的重要方法,下列有关CO2与CO的知识归纳错误的是
A.A
B.B
C.C
D.D
By the time I _____the railway station, the train _____. [ ]
A. got to, left
B. reached, had left
C. arrived, had left
D. came, left