题目

慢性粒细胞白血病的致病机理是2号染色体与9号染色体发生了交换，导致酪氨酸蛋白激酶过度活化，引起细胞增殖失控。此病患者的白细胞数量是正常人的10～25倍。下列有关说法不正确的是A. 正常人产生白细胞的速度比此病患者的慢B. 染色体之间的交换属于基因重组C. 可以通过控制酪氨酸蛋白激酶的活性来抑制细胞异常增殖D. 酪氨酸蛋白激酶过度活化是这种白血病的致病原因 　　As kids, my friends and I spent a lot of time out in the woods．“The woods” was our part-time address, destination, purpose, and excuse．If I went to a friend’s house and found him not at home, his mother might say, “Oh, he’s out in the woods, ” with a tone(语气)of airy acceptance．It’s similar to the tone people sometimes use nowadays to tell me that someone I’m looking for is on the golf course or at the gym, or even “away from his desk．” For us ten-year-olds, “being out in the woods” was just an excuse to do whatever we feel like for a while． 　　We sometimes told ourselves that what we were doing in the woods was exploring(探索)．Exploring was a more popular idea back then than it is today．History seemed to be mostly about explorers．Our explorations, though, seemed to have less system than the historic kind：something usually came up along the way．Say we stayed in the woods, throwing rocks, shooting frogs, picking blackberries, digging in what we were briefly persuaded was an Italian burial mound． 　　Often we got “lost” and had to climb a tree to find out where we were．If you read a story in which someone does that successfully, be skeptical：the topmost branches are usually too skinny to hold weight, and we could never climb high enough to see anything except other trees．There were four or five trees that we visited regularly－tall beeches, easy to climb and comfortable to sit in． 　　It was in a tree, too, that our days of fooling around in the woods came to an end．By then some of us has reached seventh grade and had begun the rough ride of adolescence(青春期)．In March, the month when we usually took to the woods again after winter, two friends and I set out to go exploring．We climbed a tree, and all of a sudden it occurred to all three of us at the same time that were really were rather big to be up in a tree．Soon there would be the spring dances on Friday evenings in the high school cafeteria． (1) The author and his fiends were often out in the woods to ________． [　　] A． spend their free time B． play gold and other sports C． avoid doing their schoolwork D． keep away from their parents (2) What can we infer from Paragraph 2? [　　] A． The activities in the woods were well planned． B． Human history is not the result of exploration． C． Exploration should be a systematic activity． D． The author explored in the woods aimlessly． (3) The underlined word “skeptical” in Paragraph 3 is closest in meaning to ________． [　　] A． calm B． doubtful C． serious D． optimistic (4) How does the author feel about his childhood? [　　] A． Happy but short． B． Lonely but memorable． C． Boring and meaningless． D． Long and unforgettable．