If we (pollute) ... the water, we will have no fresh water to use

put the verbs in bracket into the correct tense
1 if we (pollute)... the water, we will have no fresh water to use
2 if we cut down trees in the forest, there (be)... big floods every years
3 i look forward to (hear)... from you and (see)... good response from your company
4 we (burn)... trash to reduce the amount of garbage we produce to protect our environment
5 it's a good idea. let's (do)... that