1. in all directions

2. in time

3. cool down

4. be fundamental to...

5. a chain action

6. ...make it possible for...to do...

7. give birth to...

　11. prevent... from

　12. millions of years to come

　VI.Understanding.

　a.Match the phrases underlined with their correct meaning.

1.They were in time to produce carbon, nitrogen, water vapour and other gases.

　2.They multiplied and filled the oceans and seas with oxygen.

　3.Carbon dioxide prevents heat from escaping from the earth.

　4.It was not immediately obvious that water was to be

　fundamental to the development of life.

　A. increase in number B. important

C. stop/keep...from D. after a long period of time