The cross-head shoes are white metal lined, grooves being cut horizontally on the face of the white metal to ensure （）.
1、When two different metals are joined t
When two different metals are joined to form a closed circuit and exposed to different temperatures at their junctions （） which can be used to measure temperature.Aa current will flowBa power will developCa heat will flowDa pressure will produce
2、9． —How much are these white shoes?—__
9． —How much are these white shoes?—_________．AIts 10 yuanBIts 10 yuansCTheyre 10 yuanDTheyre 10 yuans
（）, the metal expands.AHeatsBHeatingCTo heatDHeated
4、The guide shoes are secured to the cro
The guide shoes are secured to the crosshead by means of（）Athrough boltsBend chock boltsCside chock boltsDtap-bolt
5、A metal object on the pier resembling
A metal object on the pier resembling a tree stump and made to receive mooring lines is a（）.AbightBbollardCchockDcamel
6、Fires involving combustible metals are
Fires involving combustible metals are classified as （）.Aclass "A" firesBclass "B" firesCclass "C" firesDclass "D" fire