清朝在满蒙藏边疆地区，乃以（）为共同的精神纽带。
A.道教
B.伊斯兰教
C.儒家
D.喇嘛教
参考答案：D
Betty had nothing for breakfast, ____________? [ ]
A. hadn't she
B. had she
C. didn't she
D. did she
煤矿安全仪器的三证一标志是防爆合格证、性能测试合格证、技术鉴定证书及（）。
