题目

下列各组物质中，相互间一定互为同系物的是       A．C4H10和C20H42                                    B．邻二甲苯和对二甲苯       C．C4H8和C3H6                                        D．一溴乙烷和1,2—二溴乙烷  答案：A解析: "Tom? Are you in bed yet?" called Mrs White. There was no answer. Mrs White put down her book and went to her 14-year-old son’s room. Tom was sitting in front of a bright computer screen on which a colourful dragon jumped and shouted. "Oh, Tom! You’re still playing on that computer. You must stop now. It’s half past eleven. If you don’t go to bed soon, you’ll be very tired tomorrow," said Mrs White. "But I’ve nearly beaten the dragon," said Tom. Mrs White could see the excitement on her son’s face. She sat down beside him. "You are always playing on that computer. You spend more time with this machine than with your family," she said with a smile. "What’s special about it? Show me what it can do!" "I think this is a great computer, Mum!" he said happily. "The hardware (硬件) is good. There’s so much memory and it has some wonderful software programs. This game, ’Dragon Player’, is my favourite, but I sometimes borrow games from Daniel and other friends. I don’t have to worry about any infected（感染） disks because I have a virus（病毒） detector (探测器) which can go over any disk and check it for viruses. Let me show you!" Tom began tapping. The screen changed in answer to his orders. "Oh, Tom," laughed Mrs White. "I’m sure it’s a wonderful computer, but I’m afraid I don’t know what you’re talking about."【小题1】When Mrs White was calling Tom, he was ______.A．playing computer games in’ his bedroomB．playing with a dragon in his bedroomC．playing "Dragon Player" in the studyD．lying in bed reading a book【小题2】 Tom was excited because ______.A．the computer has a good memoryB．the hardware is goodC．he had nearly won the gameD．his mother came to see him【小题3】 What do we know about Mrs White?A．She loves her son too much.B．She loves computer games too.C．She is very hard on his son.D．She is as wonderful as the computer game.