问题
选择题
某种动物的雌性体细胞中有11对常染色体和XX两条性染色体，雄性体细胞中有11对常染色体和X、Y两条性染色体。观察其细胞分裂过程，不可能出现的观察结果是[ ]
A．卵巢的某些细胞中有48条染色体
B．精巢的某些细胞中有12个四分体
C．卵巢的某些细胞中没有同源染色体
D．精巢细胞中都有Y染色体
答案
答案：D
搜题请搜索小程序“爱下问搜题”
某种动物的雌性体细胞中有11对常染色体和XX两条性染色体，雄性体细胞中有11对常染色体和X、Y两条性染色体。观察其细胞分裂过程，不可能出现的观察结果是[ ]
A．卵巢的某些细胞中有48条染色体
B．精巢的某些细胞中有12个四分体
C．卵巢的某些细胞中没有同源染色体
D．精巢细胞中都有Y染色体
答案：D
完形填空（共15小题；每小题1分，计15分） 阅读下列短文，从文后各题所给的四个选项中选出一个最佳答案。 Do you know how to study __1__ and make your study more effective (有效的)? We all know that Chinese students usually study very hard for long __2__, This is very good ,but it doesn’t__3__a lot ,for an effective student must have enough sleep ,enough food and enough rest and __4__. Every day you need to go out for a walk or visit some friends or some nice places. It’s good for your__5__. When you return __6__your studies, your mind will be refreshed(清醒)and you’ll learn more__7__study better. Psychologists (心理学家) __8__ that learning takes place this way. Here take English learning __9__ an example. First you make a lot of progress（进步）and you feel happy. __10__ your language study seems to stay the same. So you will think you’re learning nothing and you may give __11_. This can last for days or even weeks, yet you __12__ give up, and at some point your language study will again take another big __13__. You’ll see that you really have been learning all along. If you get enough sleep, food, rest and exercise, studying English can be very effective and __14_ . Don’t give up along the way. Learn __15__ ,you are sure to get a good result(结果).
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