I.
1. cycled
2. studies
3. have polluted
4. will be
5. doing
6. sing
II.
1. in
2. since
3. although
4. with
5. from
III.
1. volcanic
2. culture
3. heavily
IV.
1. can
2. what
3. learn
4. written
5. to
6. friendship
V.
1. a cold front
2. last an hour
3. Thunder is produced by lightning/ by heating and cooling air quickly.
4. After the lightning disappears the air cools and contracts.
VI.
1. I wish I could help you now.
2. If she slept enough, she would feel healthy.
3. I suggest we go out for a walk.
4. The weather forecast which my grandma is watching says it will be sunny tomorrow.
VII.
1. Five million bottles of champagne will be produced in France next year.
2. Although he is very rich, he still goes to work everyday.