题目

— It’s getting late. Mother must be waiting for us to have dinner.   — In that case, we ______.   A. had better leave                   B. must have left     C. need have left                     D. might leave   答案：A14．如图，在Rt△ABC中，∠A=90°，D、E分别是AC、BC上的点，且∠ADB=∠CDE=30°，BE=4CE，若CD=$\sqrt{3}$，那么BD的长为4．