1) to cover 5) the field
2) to deal with 2) the cells
3) to come from 8) a theory
4) to search for 1) clues
5) to examine 7) the word
6) to investigate 3) the problem
7) to develop 10) the basis
8) to divide into 9) groups
9) to provide 6) facts
10) to shape 11) the views
11) to invent 4) tools
1C twin16C about 2C on 17C trip 3B fridge18C go 4C some19A table 5A sixth 20A polluted 6B on 21C arrive7 B can't 22A knocked 8A freezing 23B ago 9B out 24A mustn't 10B brush25C going 11b teach 26C park 12B about 27A smaller 13A is making 28C centre14B exchange 29B rules15B show 30B needn't
1) refused going to the theatre
2)moving to the countryside
3)to by a new flat
4)working hard
5)buying a house
6)answering the questions
7)watching by millions people