人教版高二unit13学案

23 available adj.

1 These tickets are available for one month.

2 He is not available for the job.

3 They have tried all available means to the open.

24 mass

a/ A litre of gas has less mass than a litre of water.

b/ A great mass of snow has fallen off the roof.

c/ I have masses of work to do.

d/ v. Dark clouds massed and we expected rain.

25 float

a/ vi. Wood floats on water. A balloon is floating in the sky.

b/ vt. There was enough water to float the ship.

c/ on the float float off

26 absorb

Cotton gloves absorb sweat.

be absorbed by… be absorbed in… absorb sb’s attention

27 stable

A stable government is essential to economic growth.

28 sensitive

The child is sensitive to eggs.

29 mix with

mix vi. Oil does not mix with water.

mix…into… Don’t mix cotton with wool.

30 break down

a/ Rocks break down into dirt after many years.

b/ Unfortunately, our car broke down half way.

c/ Hearing the sad news, many people broke down and wept.

d/ His health broke down as a result of endless hard work.

31 freezing/ frozen

When the temperature is below freezing, water will freeze.

The water pipes froze.

True or false:

1 Water is a liquid at room temperature, and it has a relatively high freezing point.

2 The reason why water can dissolve most substances on earth is that water has high heat capacity.

3 Pure water has a higher freezing point and lighter than salt water.

4 The salinity of the earth’s ocean is about 3.5%.

5 When water freezes, its density increases.

6 Other resources such as oil, gas, gold etc is as precious as a drop of rain.

Choice:

1 What is the meaning of the sentence:“ …and we have yet to learn much about them”?

A We have already known a lot about them. B We have known a little about them

2 The salinity of the Dead sea is sure the salinity in the ordinary ocean.

A much high than B much higher than C less high than D less higher than

3 It is that makes the seaside city remain somewhat cool in summer.

A the heat capacity B the water structure C the ocean motion D the density

4 The water moving about 200 meters down is the depth where can’t reach.

A the fishes B the marine life C the sun D the earth

5 The water in the ocean also keeps the temperature of the earth somewhat by ……

A un changeable B changeable C fast D motionless