单项选择题
The internal part of boiler should be welded by yard if found （）.
A.sealed
B.cracked
C.shape changed
D.deformed
点击查看答案&解析
相关考题
-
单项选择题
The internal part of the boiler, if found （）, has to be chemically washed by yard.
A.deformed
B.rusted
C.cracked
D.scaled -
单项选择题
Centrifugal pumps can be designed with a number of impellers （） to attain a high final delivery pressure.
A.in series
B.in parallel
C.either A or B
D.None of the above is tree -
单项选择题
Which of the following pumps are self-priming, and can deal with liquid from a level below the pump: （） (1)reciprocating (2)vane (3)gear
A.（1）only
B.（1）and（2）
C.（2）and（3）
D.（1），（2）and（3）
