高级抹灰表面平整度的允许偏差为______。
A.1mm
B.2mm
C.3mm
D.4mm
参考答案:B
52. _____ I went to the hospital to see Jack, who had _____ had an operation.
A.Just now; just now
B.Just now; just
C.Just; just
D.Just; Just now
有一恒定出流的薄壁小孔口如图示,作用水头H0=4m,孔口直径d=2cm,则其出流量Q为()。
A.1.82×10-3m3/s
B.1.63×10-3m3/s
C.1.54×10-3m3/s
D.1.72×10-3m3/s