48b women was

49a lived

50c participation

IV.1 This dress shouldn't be washed with cold water

2 The wine should be opened about 3 hours before you use it

3 Books may be kept by members for 3 weeks

5 The car has to be repaired

6 The animals musn't be fed by visitors

7 Those books should be taken back to the library in time

8 Articles which customers have bought cannot be changed during the sale

9 This kind of fast food can be bought in any supermarket

10 These medicines should be kept in a cool place

12 A speech about global warning must be made by Mr.John

13 It must be dry-cleaned

14 This point of grammar will be explained by the teacher of English tomorrow

15 This building construction will be completed next month

16 The poverty problem should be solved as soon as possible by the goverment

17 Our teeth should be brushed at least twice a day

18 Silk clothes had better be washed by hand

19 The environment should be protected to slow down global warning

20 Our children should be taken care of carefully