Сделайте пожалуйста 8 и 9 задание

Exercise 8
1. The Mississippi River is the greatest waterway in the United States.
2. The Mississippi begins as a tiny stream.
3. The Mississippi river is cleaner than the Missouri River, and the Missouri River is muddy.
4. The best part of our visit was a boat ride.
5. Billy has caught a worse cold than he had last year.
6. The mountains in the west are higher than the mountains in the east.
Exercise 9
1. A lot of time was wasted when we were looking for the right house.
2. A lot can be done to stop the destruction of forests.
3. Nuclear weapons mustn't be used.
4. A lot about extinct animals of our planet will be told by biologists.
5. The text ought to be rewritten to make it look nicer.
6. These fragile cups should be packed very well, or they may break.