III. Put the correct form of the verb in brackets.
     21.If  there (be)……no wars , people ( become)………happy.
     22. If today ( be)……….Sunday, we ( have ) ………. a lot of fun.
     23.The earth is seriously   polluted. I wish it ( not be) ……. polluted like that.
     24.What …………..you ( do) ……..if you ( see) ……..a UFO ?
     25.If you ( practice) ……..English with a native speaker, your pronunciation ( improve) …….
     26.We ( save) ……………a  lot of natural  resources if we ( use) …….solar energy.
    27. If I ( be ) ……….you, I ( not accept)……. his invitation.
    28. What a pity she is not here.  If she ( be) …..here, we ( have) ….. lots of fun.
    29. I may be free tonight.  If I ( be) ……. free tonight, I ( come) ….. to see you.
    30.John wishes he (  have) ……….a good job in the future.
    31.It’s too cloudy for  the picnic today. I wish the sun ( shine)…….. right now.