Choose A, B, C or D that best completes each of following unfinished sentence

A. becomes

B. become

C. becoming

D. became

A. do they

B. don’t they

C. did they

D. didn’t they

A. diversity

B. ecological balance

C. vehicle emissions

D. single

A. Made

B. Have made

C. Having make

D. Having made

A. saying

B. having said

C. say

D. to say

A. forests

B. soil

C. water

D. fossil fuels

A. read

B. have read

C. have been reading

D. had read

A. have studied

B. have been studying

C. are studying

D. study

A. achievement

B. healthcare

C. quality of life

D. transportation

A. cheat

B. cheated

C. having cheated

D. being cheated