26. ‘Students’ in the United States ‘often support’ ‘themselves’ by baby sitting, A B C working in restaurants or ‘they drive’ taxicabs. D 27. Bill was very young when they ‘left’, and he ‘could not’ ‘longer’ remember A B C ‘living’ in the house. D 28.Hardly ‘I had got’ onto the motorway ‘when’ ‘I saw’ two police cars A B C ‘following’ me. D 29. Statistics ‘are’ now ‘compulsory’ for all students ‘taking’ a course in A B C ‘engineering.’ D 30. The ‘organization’ aim ‘is to educate’ ‘the public’ about the ‘dangers’ of smoking. A B C D giúp em vs ạ giải thích nữa em cảm ơn