问题
选择题
蝌蚪生活在水中，它的呼吸器官是（ ）
A．肺
B．皮肤
C．鳃
D．肺和皮肤
答案
青蛙属于两栖动物，其幼体蝌蚪生活在水中，用鳃呼吸，成体青蛙既能生活在陆地上，又能生活在水中，主要用肺呼吸，皮肤辅助呼吸．其幼体和成体在形态结构和生活习性上有很大差异，叫变态发育．可见C符合题意．
故选：C
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蝌蚪生活在水中，它的呼吸器官是（ ）
A．肺
B．皮肤
C．鳃
D．肺和皮肤
青蛙属于两栖动物，其幼体蝌蚪生活在水中，用鳃呼吸，成体青蛙既能生活在陆地上，又能生活在水中，主要用肺呼吸，皮肤辅助呼吸．其幼体和成体在形态结构和生活习性上有很大差异，叫变态发育．可见C符合题意．
故选：C
Dear daughter, You are a wonderful person and your mother and I think the world of you. It will not be long before you leave home to make your way in the world. Can I please give you some friendly advice? Here are some things that you should never do. 1. Never Look Down Upon Yourself. You are great and able to achieve great things so believe in yourself. When things go badly, never stop believing. Some girls get upset, blame themselves and lose self-esteem. All kinds of problems can follow. 2. Never Get Obsessed With Your Appearance. We think you look great (though some of the clothes you wear worry us!). Please be happy with the person ,you are and the body you have. Eat reasonably, take exercise and be healthy. Some girls show too much concern about losing weight or getting the perfect shape. You look fine. 3. Never Compromise Your Personal Safety. Never put yourself at serious risk. This means that you cannot trust people until you really know them and that sometimes you have to avoid things that look like they might be fun. Never get drunk or take drugs. Unluckily there are some bad people out there and it is best not to take risks. 4. Never Give Less Than Your Best. We are very proud of what you have achieved so far. You should be proud too. Keep doing well. Keep trying your hardest at everything you do. No one can ask for more than that. 5. Never Forget That Your Parents Love You. Whatever happens in life, your family will still be your family. Whatever difficulties you meet with, you can always talk to us and we will try to help. We are here for you. 小题1: Why has the father written the letter to his daughter?
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