21b

22a

23a

24c

25b

26. A => breathe

27. B => pass

28 . C => because

29. B => the most

30. B => cycle

31. No river in the world longer than the Nile river

32. Because I have a lot of homework, I can't watch TV with you

33. If we study hard, we will pass the exam

34. I started working in this company six years ago

35. We might go to the Moon for our summer holiday in 2050

36. Could he play tennis at the age of eight ?

37. Robots will be able to recognise our faces in the future

38. If we reuse bottles, we will save a lot of money 

39. My brother can't make the bed

40. Ha Noi is the capital of Vietnam

Chúc bạn học tốt nhé ! 
Cho mik 5* và câu trả lời hay nhất !