Raw lacquer is（）corrosive nature．

1、With （）, the corrosion problems are mu

With （）, the corrosion problems are much reduced in a central cooling system.Ano equipment in contact with sea waterBless equipment in contact with fresh waterCmore equipment in contact with sea waterDless equipment in contact with sea water

2、The natural order hypothesis is presum

The natural order hypothesis is presumed by Krashen to be the result of the learned system, operating free of conscious grammar.（）A正确B错误

3、The strongest of the natural fibers is

The strongest of the natural fibers is（）.AcottonBhempCmanilaDsisal

4、Exhaust valve grooving and corrosion i

Exhaust valve grooving and corrosion is caused by certain components of residual fuel oilThese components are sodium, sulfur, and （）.AvanadiumBcarbonCcopperDash

5、Corrosive liquids and acids should hav

Corrosive liquids and acids should have what kind of label? （）ASkull and crossbonesBYellowCRedDWhite

6、It is human nature to think back to a

It is human nature to think back to a Golden Age（）one’s country was strong and respected.AwhenBprovidedCasDunle