题目

I was really anxious about you. You _____ __ home without a word. A. mustn’t leave     B. shouldn’t have left      C. couldn’t have left    D. needn’t leave 答案：B 解析: 从题意分析，对方没有打招呼就去了，造成的结果是I was really anxious,故B表示过去不应不打招呼就走。18．已知直径CD⊥弦BF于 E，AB为?O的直径．（1）求证：$\widehat{FD}$=$\widehat{AC}$；（2）若∠DAB=∠B，求∠B的度数．