Complete the sentences with the correct conditional form of the verbs in brackets.
1. If you ________________ (want) to have a greener house, ________________ (grow) some grass on your balcony or roof.
2. ________ (not/use) air conditioning unless you really ________________ (have) to.
3. If you_______ (feel) strongly about saving our planet,________ (act) now!
4. Unless we________ (plant) new trees now, there ________ (not be) any forests left.
5.If the weather________(is) nice, ________ (leave) the car at home and walk.