Ex 8 Rewrite the sentences using
if and unless
1
Train regularly or else you won't be ready in
May
If you don't train regularly, you won't be ready
in May./Unless you train regularly, you won'
be ready in May.
2 Listen to the coach or you won't know what
to do.
3 We'd better hurry or we'll miss the start of
the match.​

The nature and the person are closely connected. And if the nature can exist without person, then the person without it can't. Therefore it is so important to live in harmony with the nature.
But, unfortunately, people try to subordinate to themselves the nature, to become her owner, but so it is impossible. The nature needs to be protected, it is our house. Necessary for life the nature gives all to us. If was considered earlier, the natural riches which aren't settled that they in large quantities, then now it becomes clear what is in limited quantity much. The person can't use gifts of the nature constantly as they can disappear soon. A task of the person to preserve the nature and to increase her riches. It is necessary to approach the matter as we are obliged to leave behind to the descendants the rich, beautiful, and pure planet responsibly.

1. I can’t remember …seeing him before (to see). 
2. The machine needs cleaning… (to clean). 
3. She is angry at … for sending (to send). ??? 
4. You should avoid breaking… rules (to break). 
5. She entered the office without  noticing… (to notice). 
6. I am sorry for …disturbing you (to disturb). 
7. We can’t excuse their not …answering our invitation (to answer). 
8. The cat was punished for …breaking the cup (to break) 
9. The cat was afraid of  punishment (punishing)… and hid itself under the sofa. (to punish). 
10. After looking… through and  marking… the student’s papers, the teacher handed them back. (to look),(to mark).