题目

 如图，△ABC内接于⊙O，弦AC交直径BD于点E，AG⊥BD于点G，延长AG交BC于点F．  求证：AB2＝BF·BC．  答案：证明：延长AF，交⊙O于H.∵直径BD⊥AH，∴= .                         ……………………2分∴∠C=∠BAF.                                    ………………………3分 在△ABF和△CBA中，∵∠BAF =∠C，∠ABF=∠CBA，∴△ABF∽△CBA.                    ………………………Mom noticed that something was wrong when I started getting so thirsty. I’d have a lot to drink before bed, which was unusual for me. One time, I opened a big container of apple juice and kept refilling my glass. Before I knew it, I’d drunk the entire container! My mom called my doctor. I then had a few blood tests, and the results were certain — I had diabetes (糖尿病), which meant that the amount of sugar in my blood was very high. That can be dangerous, so I had to learn how to control my blood-sugar level. My eating habits had to change in a big way. With diabetes, I can’t eat a lot of sugar or carbohydrates (碳水化合物). I have to figure out exactly how much sugar I plan to eat, and then I get an injection of insulin (注射胰岛素) before the meal to help my body process the food. Also, I test my blood-sugar level often. I’m always trying to keep my blood sugar at a healthy level. The level can drop when I exercise, but that doesn’t keep me out of gym class or off the basketball court — I just keep some juice boxes around to boost my blood sugar if I need to. It’s a lot of work — and not a lot of fun — to keep track of everything, but I’ve gotten used to my new habits. I was a little scared at first because I wasn’t sure how my life would change. Once I knew what I needed to do, though, it wasn’t a big deal. My life is different now from what it was before, but it has become completely regular to me. 【小题1】The first paragraph is mainly about _____.A．who found the author had diabetesB．the author’s life before having diabetesC．how the author was found to have diabetesD．the author’s eating habits before having diabetes【小题2】What did the author do after knowing she had diabetes?A．She stopped playing basketball in the gym.B．She controlled her blood-sugar level strictly.C．She stopped eating food with natural sugar.D．She tested her blood-sugar level before every meal.【小题3】What does the underlined word “boost” in Paragraph 2 mean?A．Increase.B．Control.C．Absorb.D．Test.【小题4】What’s the author’s attitude toward her having diabetes now?A．Worried.B．Frightened.C．Pessimistic.D．Positive.