题目

p{font-size:10.5pt;line-height:150%;margin:0;padding:0;}td{font-size:10.5pt;}（09年揭阳市期末）（15分）如图所示，光滑斜面倾角为，一个重20N的物体在斜面上静止不动。轻质弹簧原长为10cm，现在的长度为6cm。(1)求弹簧的劲度系数；(2)若斜面粗糙，将这个物体沿斜面上移6cm，弹簧与物体相连，下端固定，物体仍静止于斜面上，求物体受到的摩擦力的大小和方向。 Most children like chocolates, candies and other kinds of sweet food. Sometimes they put a lot of sugar into their food. They don't know that sugar is bad for their teeth. Children also like fast food. It is ___ ____ delicious than home cooking, and children can take it away and eat it anywhere. Other children like to eat too much meat. Fast food or too much meat doesn't help build a strong and healthy body.Children grow fast. They need to eat more eggs, milk, corn(谷物),fruit, vegetables and other healthy things. Eggs and milk are good for their bones. Corn gives them energy. Fruit and vegetables give them vitamins(维生素). Children should eat an egg, and have about 200ml of milk every day. It's best to drink milk after eating bread in the morning. They should eat 150g of corn to give them energy, too. They should also eat an apple or some other fruit with their breakfast. Eating enough vegetables is important for lunch and supper.1.How many kinds of healthy foods are mentioned(提及) in this passage?A. Three B. Five C. Six D. Seven2. According to this passage, we ______.A. shouldn't put any sugar into their foodB. should eat more fast food to make us strong and healthyC. should eat corn to keep us activeD. shouldn't drink milk after eating bread3.选择最佳答案,填在空白处。A. much B. a littleC. much more D. very4.What does the underlined word "build" mean?A. buy B. let C. have D. make5.What's the main idea of this passage?A. Children shouldn't eat sweet food.B. Children grow quickly.C. Children should eat home cooked food instead of fast food.D. Children should eat more healthy foods.