When air is at its dew point it is at

1、It is assumed that students at an inte

It is assumed that students at an intermediate level will have a good（）of the basic structures and vocabulary of English.AcommandBcommandingCto commandDcommanded

2、The dew point of air is reached when t

The dew point of air is reached when the wet bulb temperature is （）.ATwice the dry bulb temperatureB10℃ above the dry bulb temperatureC5℃ above the dry bulb temperatureDEqual to the dry bulb temperature

3、At the same time，it is（）for you to sig

At the same time，it is（）for you to signify your acknowledgement of the responsibility for the collision by signing the copies of this letter hereto attached and to return me two copies in due time.AessentialBimportantCgoodDa better operatio

4、What is it called when it is possible

What is it called when it is possible to ignite the vapour above the oil?（）AFlash pointBBoiling pointCIgnition pointDPour point

5、The dew point is reached when the（）.

The dew point is reached when the（）.Atemperature of the air equals the temperature of the seawaterBatmospheric pressure is 14.7 lbs. per square inchCrelative humidity reaches 50%Dair becomes saturated with water vapor

6、（）at the railway station when it began

（）at the railway station when it began to rain.AHardly had he arrivedBHardly he had arrivedCNo sooner did he arriveDNo sooner arrived he