Rewrite the following sentences 
19, Although Mr.Anderson didn't speak Vietnamese,he decided to settle in Hanoi 
-> In spite ....
20, We don't see our grandparents very often because they live so far away 
-> IIf....
21, The weather was awful. We didn't enjoy our camping holiday ( due to) 
-> .... 
22, Rescue workers have freed many people in the collapsed buildings 
-> Many people....
23, Aquatic life suffers or does because there is thermal pollution ( because of) 
-> ... 
24, Palstic bags are non-biodegradable. They will remain in the environment for many years
-> Since....
25, We are unable to see the stars in the sky. Light pollution occurs (makes) 
-> ....
26, We had lunch then we took a bus to travel around the city 
-> After.... 
27, The storm destroyed everything except the bamboo tree( by) 
-> .....
28, My grandfather is very old. He is still young at heart
-> Although....
29, You can't have a good health unless you exercise more 
-> If ....
30, They will organize a garden party to raise money for the victims of the flood
-> A garden party....
31, There was a loud noise next to my door last night so I couldn't sleep
-> As...