1. When do you have Chemistry

2. What is her favourite subject?

3. How many employees do the library in this city have?

4. When will you have an English test?

5. Where do their family often travel to in summer?

17. C.useful

18. C.wants

19. D.have you

20. A.telling

21. B. are

22. A.for

23. D. a few

24. C.successful

25. B.next

26. B.These

27. C.number

28. C.If

29. D. or

30. A.gets

   (1/2a + b)^3 + (1/2a - b)^3 

= ( 1/2a+ b + 1/2a  - b) [ (1/2a + b)^2 - (1/2a + b)(1/2a - b)+ (1/2a - b)^2)]

= a ( 1/4a^2  + ab + b^2  - 1*4a^2 + b^2 + 1/4a^2 - ab + b^2)

= a . ( 1/4a^2 + b^2)

= 1/4a^3 + ab^2

orctober --> october

cafeteriea --> cafeteria

poppular --> popular

econormics --> economics

voluntreer --> volunteer

marblies --> marbles

ortchestra --> orchestra