(
课件网) Unit 4 Lesson 12 Healthy Bones How much do you know about your bones How to keep your bones healthy 人的骨头，早在胎龄二月时就开始形成。此后不断生长，女子到二十岁左右骨头才停止生长，男子则长到二十五岁左右。 人的骨骼，一般在十八岁左右长度就稳定了，也就是说不会再长高了。但是，骨的密度还要继续增加。四十岁后，骨的密度就开始显示出下降的趋势。下降的快慢，则要看人的体质情况而定。一般是体力活动多或喜好运动的人缓慢些。 成人骨头共有206块，分为头颅骨、躯干骨、上肢骨、下肢骨四个部分。但儿童的骨头要比大人多11～12块，就是说有217～218块。医学书上说，初生婴儿的骨头竟多达305块。人体最长的骨头是股骨，即大腿骨，它通常占人体高度的27%左右，有记录的最长腿骨为75.9厘米。而耳朵里的镫骨是人体内最小的骨头，它只有0.25～0.43厘米长成年人骨的重量约为体重的1/5，刚出生的婴儿骨重量大约只有体重的1/7。 although, but conj. although的意思是“尽管，虽然”，用来引导让步状语从句，在一般情况下可以和though互换，但though比较口语化，而although较为正式，另外although的语气比though重。当although / though引导的从句放在句首时，主从句之间要用逗号隔开。 but引导的从句多放在主句后。 although & but Although / Though he was tired, he kept on working. 虽然他已经累了，但仍然继续工作。 He often helps me with my English although he is quite busy. 尽管他相当忙，但是还常常帮我学英语。 His office is in New York, but he is often away. 他的办公室在纽约，但他经常不在。 注意： although和though引导的从句不能与but连用，但可以互换。 如： Although we are poor, we are still happy. = We are poor, but we are still happy. 我们虽然穷，但是活得很开心。 Choose the main idea of each part. Part 1(para. ) Part 2(para. ) 1-2 3-5 A. Bones are light but very strong. C .Calcium can make bones solid. B. The introduction of bones. D. Ways to keep bones healthy. Read the first paragraph and answer three questions. 1.Why are bones important 2. Are our bones light 3. Can bones support our weight Because they support our bodies and help us move freely. Yes, they are. Yes, they can. Why can bones support our weight Read the second paragraph, draw a picture of bone structure and take some notes. Look at the Sentence Builder. Grammar 1. Although they are light, bones are strong enough to support our weight. 2. Bones are hard on the outside, but they are soft on the inside. although意为“虽然，尽管”，通常位于_____。 but意为“但是”，通常位于_____。 句首 句中 They are light, but bones are strong enough to support our weight. =Although they are light, bones are strong enough to support our weight. 【注意】although与but不能同时用于一个句子中。 Find more sentences contains “Although or but”, and change them into another forms. Bones are important because they help us move freely. = Bones help us move freely, so they are important. because意为“因为”，表示_____。 so意为“因此，所以”，表示_____。 原因 结果 Look at the Sentence Builder. 【注意】because与so不能同时用于一个句子中。 Find more sentences contains “because or so”, and change them into another forms. on the outside ... ...
