B
Below is a table which shows the melting(液化)and boiling points of common substances.Study the table.Then do Numbers 4—7.

Substance	Melting point(C)	Boiling Point(C)
Water Alcohol Nitrogen Oxygen	0 –117 –210 -218	100 78 –196 –183

4.The underlined word‘substances'means‘a type of'_________.
A.matter        B.liquid            C.solid         D.gas
5.Which of the four should be a liquid at-90 degrees?
A.water         B.alcohol           C.nitrogen      D.oxygen
6.Mixing alcohol and water is often used to wash windscreens of cars during the wintertime because _________.
A.it is easier for alcohol to change into gas
B.alcohol is not easily separated from water
C.alcohol freezes at lower temperature than water
D.the mixture is not expensive
7.In order to change water from a solid to a liquid energy must be _________.
A.removed       B.added             C.created       D.destroyed