能选择性地与组胺结合的受体是
A．M受体
B．N受体
C．α受体
D．β受体
E．H受体
参考答案：B
— He didn’t come to school yesterday, did he ?
— _________.He was ill in bed.
A．Yes, he did
B．No, he didn’t
C．Yes, what a pity
D．No, I think
机械除锈法主要有手工除锈，手动和电动工具除锈、（）除锈。
A.喷丸
B.化学
C.喷砂
D.打磨
