nối cột 1 vs cột 2:
1/ i asked him. a/when a volcano will erupt
2/ we can usually predict b/if we go on littering
3/ i wish c/i could visit your village again some day
4/ the parkers are nice d/so van feels like a member of their family
5/lan enjoyed the peaceful atmosphere e/while maryam was praying
6/the environment will become seriously polluted f/ whether he taught other foreign languages besides
english