B/1-Air pollution/common environmental problem/throughout/world

2-Therefore/if/want/protect/environment/pollution/we/should/do/following/thing
3-Firstly/we/should/reuse/used class/newspaper/bottle/instead/throw/thêm/away

4-Secondly/we/should/travel/bicycle/public transport
5-Thirdly/we/must/stop/burn/coal/produce/electricity
6-If /we/try/do/all/we can,/environment/cleaner.


D/1-Sun/effective/source/power

 2-It/be/cheap

3-It/be/clean

4-It/not cause/pollution
5-Solar panels/be installed/roof/house/receive/energy

/the sun

6-It/can/store/a number of days

7-It/be used/cloudy days

8-Solar energy/provide/enough power/world's population
9-We/save/natural resources/use/solar energy/instead/gas,oil and coal

10-Therefore/lot/countries/world/already/use/solar energy