----- Nội dung dịch tự động từ ảnh ----- IV. Mark the letter A, B, C or D to indicate that underlined part that needs correction in each of the following sentences. 21. It's difficult study in a foreign country, so students need to prepare for the experience. C D 22 I'm tired of being told what writing about tram system in Hanoi. A B A B D 23 In 1939, no more than 15 percent of all school-age children received any kind of school. A в D 24 It's convenient of us to take a cycle and observe life in Ho Chi Minh City. А в с 25. I had just finished my meal when he had called me out for dinner. D A B D 26. The menu has been already changed, but the customers are still complaining about the lack of A B C D variety. 27. I was surprising to learn that there was a tram system in Hanoi a century ago. A в D 28. A new rail system in Hanoi is expected to complete in the next few years. A B D 29. You'd better to listen to each other's ideas when living in an extended family. A в D 30. A new advanced water treatment plant which will eventually serve 300,000 customers is now A on construction D