​1. My dog/ always bark/ if/ hear/ strange sound.
2. She/ be late/ work/ because/ miss/ bus.
3. She/ not work/ hard/ because/ be/ old.
4. If/ homework/ not be/ long and difficult/ I/ finish/ on time.
5. She/ not read/ books/ because/ not have/ enough time.
6. We/ not go/ a walk/ because/ it/ rain/ heavy.
7. If/ people/ stop/ use dynamite/ fishing/ sea creatures/ be well preserved.

Write correct sentences to make a complete letter:
1. I/ write/ you/ bad situation/ affect/ lake/ school.
2. As you know/ late/ school/ be beautiful.
3. However/ it/ become/ polluted.
4. People/ electricity/ fish.
5. A lot/ fish/ die/ float/ water surface.

Conplete the sentences with an appropriate form of the words in parentheses :
1. The air in the city is very .........( pollute)
2. Please listen to the lecture ...........( care )
3. The accident happened because of driving ........( care)
4. He is going to ......... all the bags.( collection )
5. She has .............  provided a picnic lunch for us.( kind)
6. We'll make this beach clean and .......... again.( beauty)
7. If the .......... continues, what will happen? ( pollute)
8. He was ........... that they were not coming.( disappoint)
9. Air and water ......... can make people fall ill.( pollute)
10. A large number of inhabitants have made ............. on how to protect the environment. ( suggest)