竣工验收之前,给水管道做强度严密性试验、冲洗试验、通水试验;排水管道做通球试验、通水试验;消防管道做强度严密性试验和()。
A、灌水试验
B、冲洗试验
C、通球试验
参考答案:B
ff the economy is just beginning to come out of a recession, which of the following would represent a typical sequence of phases in the business cycle()
A. Expansion, business peak, contraction, recessionary trough.
B. Expansion, business peak, recessionary trough, contraction.
C. Depression, expansion, business peak, contraction.
溶液与我们的日常生活密切相关,下列有关溶液的说法正确的是( )
A.溶液一定是无色透明的液体
B.汽水和食盐水都属于溶液
C.某物质在100g溶剂里达到饱和状态时所溶解的质量就是该物质的溶解度
D.将澄清的饱和石灰水加热,无白色浑浊出现