题目

I’ve become good friends with several of the students in my school __________ I met in the English speech contest last year. A．whoB．whereC．whenD．which 答案：A解析: 略2．如图，在Rt△ABC中，∠C=90°，AB=13，AC=12，则∠A的正弦值为（　　）A．$\frac{5}{12}$B．$\frac{12}{13}$C．$\frac{12}{5}$D．$\frac{5}{13}$