VII.

1. this time tomorrow/English/They/will be learning.
=>They will be learn English tomorrow
or they are learning English at this time
2. to save/will reduce/our energy/the use of electricity/We.
=>We will reduce to save the use of electricity
3. biogas/is/cooking and heating/I think/for/abundant and cheap.
=>I think biogas for cooking is abundant and cheap
4. we use/travelling long distances/public transportation/Will/when/?
=>Will we use public transportation when travelling long distances?

VIII.

1. We will use sources of energy more effectively for our future.

=> Sources of energy will be used more effectively for our future.

2. We will solve the problem of energy shortage by using solar energy.

=> The problem of energy shortage will be solved by using solar energy.

3. They will replace coal by another renewable source.

=>Coal will be replaced by another renewable source.