咳嗽伴杵状指常见于()
A.风湿性心脏病二尖瓣狭窄
B.风湿性心脏病主动脉瓣狭窄
C.冠状动脉粥样硬化性心脏病
D.右向左分流先天性心脏病
E.高血压性心脏病
参考答案:D
下列计算结果正确的是 [ ]
A.2x+5y=7xy
B.2a2+2a3=4a5
C.4a2﹣3a2=1
D.﹣2a2b+a2b=﹣a2b
It's too hot. Please keep the windows _____.[ ]
A. opened
B. closed
C. open
D. is closing