焊件的缝隙大小一般为()
A.0.04~0.09mm
B.0.1~0.15mm
C.0.16~0.2mm
D.0.21~0.25mm
E.0.3~0.35mm
参考答案:B
The tall building ____________ in the center of this area will be used as a 5-star hotel.
A.to built
B.building
C.being built
D.having built
把一根火柴梗平放在蜡烛的火焰中,约1s~2s后取出,能观察到( )
A.均匀地被烧黑
B.与外焰接触部分被烧黑
C.与内焰接触部分被烧黑
D.与焰心接触部分被烧黑