地球自转产生的地理现象是[ ]
A.四季的变化
B.昼夜长短的变化
C.太阳直射点的变化
D.昼夜交替
答案:D
I had no idea she was there. I met her only____. [ ]
A. as a result
B. in surprise
C. by chance
D. in a way
胆道疾病首选的诊断性检查是()
A.PTC
B.静脉胆道造影
C.B超检查
D.口服胆囊造影
E.ERCP