Complete the sentences (1-5) using the words in brackets in the correct form. Do not use more then four words the complete each sentence.
1. Scientists believe that many animals (become/exciting) .... in the future. 2. If you (turn out/light) .... when you're not using them, you will save electricity. 3. If everyone recycled their rubbish, (it/help) .... the environment. 4. When I leave school, I (volunteer) .... in Africa for six month. 5. Unless we take care of the rainforests, many species (not/survive) .....