1 Соедини две части в предложение: 1. Don't pollute rivers...
2. Never ruin(pazopatb)...
3. Resting in the forest...
4. Keep your countryside...
5.Reduce pollution...
6. Climate change...
7. Plastic bottles
8. Walking to school...
a) don't disturb wildlife
b) clean;
c)with garbage;
d)birds' nests;
e) by recycling
f) results from global warming,
g) are recycled into supermarket bags;

1.the boiling point will be determined after the experiment begins in half an hour.2.the substance was being dissolved in nitric acid when the professor came in.3.by the end of the next experiment the volume of liquid will have been measured in a graduated cylinder.4.the result of the reaction of sulphuric acid with potassium hasn't been obtained yet.5.many experiments were carried out by pharmaceutical students yesterday.6.by the end of our practice many medicinal plants will have been  collected at the botanical stations.9.pharmacy is defined as the science of recognizing, identifying, selecting, preparing and compounding substances.10. some preparations which were known to primitive men are known in a modified form.11. it is known that morphine was isolated from opium by 1906.12. he said that the room had been ventilated for two hours before the class began.№7 и 8 дублируют №5 и 6.