Modal verbs and conditionals

If you want to reduce pollution, you ______________ take the car less often.

Unless we replace oil by renewable clean energy, we _____________ solve the problem.

If we had followed the advice of scientists, we _________________ in this situation.

Many species wouldn't have disappeared if we ________________ taken meassures before.

Don't use so many plastic bags if you _______________ to be environmentally friendly.

Some species would have dissapeared if we ...

If voters were wiser, governmets __________________ so many wrong decisions about environmental issues in the last decades.