Correct the mistakes.
1. Chemistry is the science about immune system.
2. Chemistry is concerned with the changes matter undergoes during chemical reactions.
3. Ancient Egyptians pioneered the art of dry chemistry 4,000 years ago.
4. Wet chemistry means that chemistry is done in the solid phase.
5. The genesis of chemistry can be traced to the widely observed phenomenon of cooling.
6. Starving led to the discovery of the process of purification.
7. In the XXI century an epidemic of plague gave rise to a need for medicines.
8. Gregor Mendel developed the theory of Conservation of mass.
9. Dmitri Mendeleev discovered the periodic table of the chemical elements.
10. Inorganic chemistry is the study of carbon based matter.
11. Analytical chemistry is the analysis of material samples.

i choose the correct answer

1 if you drop the vase my mother … you.

a) punishes b) will punish c) would punish

2 if she … not so slowly she would enjoy the party.

a) were b) is c) will be

3 if we had a chicken we … it.

a) cooked b) would cook c) were cooking

4 if you … my library book i will have to buy a new one.

a) will lose b) lost c) lose

5 if she … you were in hospital she would have visited you.

a) had known b) knew c) would have known

6 if i have a computer i … computer studies.

a) would learn b) will learn c) learn

7 if the weather had been nice we … go on excursion.

a) went b) would have gone c) will go

8 if i … you i would visit jane yesterday.

a) was b) had been c) were

ii put the verbs in the brackets into the correct tenses

1 if he eats all that he will be ill.

2 if he had known the whole story he wouldn't have  been so angry.

3 if we had more rain our crops would grow faster.

4 if you painted the walls white the room would be much brighter.

5 ice will turn the water if you heat it.

6 if she knew that it was dangerous she wouldn't come.

7 i would have taken a taxi if i had realised that it was such a long way.

8 the police will arrest him if they catch him.

iii form the right type of the conditionals

1 if you went to bed earlier you wouldn't feel so tired.

2 if you come to my place i will show you my collection.

3 if i knew her well i would phone her at home.

4 if she hadn't driven so fast she wouldn't have crashed.

5 if he loves her he will stay with.