题目

在△ABC中，∠C＝90°，AC＝2，BC＝2，则AB＝____，∠A的度数为____. 答案：【答案】4 60° 【解析】∵在△ABC中，∠C=90°，AC=2，BC=，∴AB=，∴sinA=,∴∠A=60°.1. Where does the conversation take place?      A. In the library.　　　　　　　　　　 B. In the classroom.　　　　　　  C. On the campground 2. Why has the woman come to talk to the man?    A. To discuss his trip to Beijing.    B. To bring him a message from Professor Grant.    C. To see what progress he's made on his paper. 3. What seems to be the man's problem?    A. He can't sleep at night.    B. He can't narrow down his research topic.    C. He can't find a quiet place to study.