1. If / we / plant / more trees / neighbourhood / greener
      ->If we plant more trees, our neighbourhood will be greener.
  2. If / we / cycle /school / every day / we /keep /air / clean and fresh
      ->If we cycle to school everyday, we will keep the air clean and fresh.
  3. If / we / keep /hunt / animals / they / disappear / soon
      ->If we keep on hunting animals, they will disappear soon.

cấu trúc keep on + Ving: tiếp tục
  4. If / we / cut down / all / trees / there / floods 
      -> If we cut down all trees, there will be floods.
  5. If / we / use / buses / we / reduce / pollution

      -> If we use the buses, we will reduce pollution.