8. People’s activities are a major cause of pollution resulting _______climate change and some disasters such as deforestation, tsunamis, etc.
A. in B. on C. at D. to
16. I wouldn’t throw litter on the ground if I ________ you.
A. are B. were C. will be D. am
17. Many people around the world ________ to the Big Ben in London for many recent years.
A. travel B. travelled C. are travelling D. have travelled