21 . Một quả cầu lăn từ đỉnh của một con dốc 100m sau 10s đến chân dốc sau đó quả cầu tiếp tục lăn trên mặt phẳng ngang thì dừng hẳn a ) tính gia tốc của quả cầu trên dốc và mặt phẳng ngang b ) tính thời goan quả cầu chuyển động c )vận tốc trung bình của quả cầu

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Finish each of the following sentences in such a way that it means exactly the same as the sentence printed before it, beginning with the word(s) given. 71. „Why didn‟t I learn to drive before?‟ thought the manager. The manager _________________________________________________________________________________________ 72. My parents find fault with everything I do. No matter____________________________________________________________________________________________ 73. The man continued to feel unsafe until they crossed the border. Not until _____________________________________________________________________________________________ 74. Kathy feels sick, as she ate so much seafood this evening. If Kathy _____________________________________________________________________________________________ 75. Tom insisted on being told the complete story. Nothing but __________________________________________________________________________________________ 76. The only thing that makes this job worthwhile is the money. Were _______________________________________________________________________________________________ 77. You should never spend other people‟s money under any circumstances. Under no ____________________________________________________________________________________________ 78. The manager was annoyed because his secretary came late to work. The manager objected__________________________________________________________________________________ 79. The only way you can master English is practicing it every day. Only by _____________________________________________________________________________________________ 80. „It certainly wasn‟t me who took your English book.‟ Tom said. Tom ________________________________________________________________________________________________