Complete sentences 

EX1complete sentences 
1 we must learn about keeping the environment ................(pollute)
2 scientists say that exhaust fumes are .... our city (poison)
3 if we (recycle) ............ more , we (help) .. ........ the Earth 
4 America (celebrate)            Thanksgiving Day on the fourth Thurday of November since 1864 
5 food and medical supplies (deliver) ............ to the victims by the rescue team yesterday
EX2  rewrite these sentences 
1 People throw rubbish in the street . The street does not look attractive
-> If ......................
2 I want to grow the vegetables but there isn't a garden at our house 
-> If ..........................
3 Acid rain is dangerous . Trees' leaves are damaged
-> Because ................
4 Noise pollution happens . There is a change in animals' ling pattern
-> Noise pollution causes ....................