IX. Finish the second sentence in such a way that it means the same as the sentence printed before:

41. The children should not stay up late.
→ The children ought not to stay up late.
42. How high is the Big Ben Clock Tower?
→ What is the height of the Big Ben Clock Tower?
43. How long is the Mekong River?
→ What is the length of the Mekong River?
44. I haven't seen her at this club before.
→ This is the first time I have seen her at this club.
45. Bill last called me five days ago.
→ Bill hasn't called me in five days.

X. Combine pairs of sentences below using the given words in the blank:

46. It will be colder tomorrow. It will be warmer tomorrow.
→ It will be colder tomorrow than it will be warmer tomorrow.
47. Lan and Ba don't have a tent. They never go camping.
→ Lan and Ba don't have a tent, so they never go camping.
48. I have to stay at home. I can finish all my exercises.
→ I have to stay at home so that I can finish all my exercises.
49. The book is very interesting. I read it twice.
→ The book is so interesting that I read it twice.
50. The work is very difficult. He can finish it on time.
→ Although the work is very difficult, he can finish it on time.

41. The children ought not to stay up late
42. What is the height of the Big Ben Clock Tower?
43. What is the length of the Mekong river?
44. This is the first time I have seen her
45. Bill hasn't called me for five days