采用正硅酸乙酯包埋料包埋,其最佳粉液比为()
A.3∶1
B.1∶1
C.4∶1
D.3∶2
E.5∶1
参考答案:A
—Can I look at the menu for a few more minutes before I decide?
—Of course. ______, sir.
A.Make yourself at home
B.Take your time
C.It doesn’t matter
D.Enjoy yourself
非金属阀在使用中应注意什么?