题干

2009年春我国许多地方出现旱情,影响农作物的生长。下列有关水对生命活动影响的叙述,不正确的是   
①越冬的植物体内自由水和结合水的比值下降,有利于抵抗不利的环境条件  ②细胞内自由水含量降低是细胞衰老的特征之一  ③癌细胞中自由水含量较正常的细胞低  ④当人体缺水时,血浆的渗透压会降低,从而产生渴觉

A:①④

B:①③

C:③④

D:②④

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答案(点此获取答案解析)

C

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    Are you scared about moving up to senior high school?It can be a new experience,but you shouldn't worry.We've put together a guide on how to survive the first week.

    You're not alone

    Remember everybody else in your year is in the same boat.They may not realize it,but they're just as nervous as you are.Moving to senior high is an opportunity,not a problem.Things are different and all you need to do is be polite and learn the new rules.

    Teachers are ready to help!

    If you're unsure what to do or are worried about anything then you had better ask for help.Teachers are probably the best people to turn to as they're experienced in helping new students.Some senior high schools also have a “friends system”.If your school has this,then you will be paired with an older student.They will look out for you and help you if you have any problems or questions.

    All change

    There are lots of differences between junior high school and senior high school.You'll have a homework diary or a student planner.You will have your lessons with different teachers in different rooms.You will have homework for different subjects on different days,so make sure you get organized.Make sure you have a copy of your school timetable written down so you know which rooms your classes are in and on which days you will have your different subjects.

Other points

    If you've got an older brother or sister at the school then ask them for advice.

    Be yourself! It sounds simple,but people will know you much better if you just act naturally.

    Having early nights makes a difference and you'll find it easier to get up in the morning!