题目

The shop near my home_____ at seven in the morning and it______ for twelve hours a day.     A. is open; opens   B. opens; is open   C. is opening; is open    D. opens; is opening 答案：B已知：在ΔABC中∠BAC=90°，AB=6，BC=10，AD⊥BC，垂足为D。（1）求AC的长；（2）求AD的长。