13. We wonder ........................the tickets are on sale yet. a. what b. when c. whether 14. When I rang Oanh some time last week, she said she was busy.................day. a. this b. that c. then d. the 15. Which word has the underlined part pronounced differently from the others? a. just b. sun c. put d. bucket 16. Which word has the underlined part pronounced differently from the others? a. instead b. head c. heap d. dead 17. Which word has a different stress in the group? a. amount b. inventor c. garbage d. resource 18. This film must be new. Weve ........................ seen it before. a. ever b. never c. since d. yet 19. He hates.......................................to do something by others. a. to be asked b. asking c. being asked d. to ask 20. Lets go camping in the mountain, ........................? a. do we b. can we c. will we d. shall giải thích