Cast iron and gunmetal fittings are used freely in small sizes at moderate pressure; large fittings, those for high pressure and temperature are cast or mild steelIn the above sentence, the word “those” means （）.
1、An iron and steel works, with several
An iron and steel works, with several satellite factories,______________in that city now.Ais builtBis being builtCwere builtDare being built
2、Many cast iron pistons are designed wi
Many cast iron pistons are designed with heat dams, which serve to （）Akeep piston crown temperatures elevated for smoother combustionBreduce th...
3、Any ships fitted with SES can（）and（）th
Any ships fitted with SES can（）and（）through the satellite system when sending a distress alert.Aenter the system / contact an RCCBaccess to ...
4、A cast steel strong back is fitted in
A cast steel strong back is fitted in way of the combustion space to help absorb （）.Aflame temperatureBfuel oilCair movementDgas force
5、The cast iron guide-ways for （） are at
The cast iron guide-ways for （） are attached to the top section and seal off the crankcase.Athe connecting rodBthe cross-headCthe piston rodDthe air box
6、Every ship must fitted with（）SART, and
Every ship must fitted with（）SART, and（）two-way VHF radio telephone.A1,2B2,3C2,1D3,2