Ex. 4 Complete these sentences. Use mustn’t or don’t have to 1. You….touch this switch. It is very dangerous.
2. You …..do this work now. You can do it later.
3. You ….add this liquid to the solution because if you do it there will be an explosion in the laboratory.
4. You ….learn this rule because our teacher didn’t include it in the examination materials.
5. I am happy because I ……carry out the experiment to produce liquid ammonia. Someone has already done it.
6. You ….touch these reactants.
7. You …. break this rule when you work with explosives liquids.
Ex. 5 Circle the best option 1. … I borrow you textbook, please?
a) must b) can c) have to d) should
2. You … dilute this solution with boric acid because it give a rise to a boomerang effect.
a) have to b) could c) must d) shouldn’t
3. I think that this substance … change its colour.
a) may b) will c) have to d) should
4. … you call me back please. I am busy now.
a) may b)could c)must d) should
5. To obtain the solution of nitric acid you……use this method.
a)may b)might c)can d) must
6. Who …..check his experimental results?
a) can b) have to c) has to d) mustn’t
7. All laboratory assistants ….follow the safety rules.
a) have to b) mustn’t c) may d) might
8. To saturate this hydrocarbon you ……study its properties at first.
a) must b) will c) can d) could
Ex. 6 Put the questions to the bold-typed words 1. Alkenes are relatively stable compounds.
2. Functional groups form a homologous series.
3. People produce this substance industrially. 4. Chemists often draw aromatic compounds as cyclic alkenes.
5. These reactants interact with one another at room temperature.
6. Electron shells have orbitals. 7. They will produce this substance tomorrow.
