胆固醇结石好发于
A．胆囊内
B．肝内胆管
C．肝外胆管
D．胆总管
E．右肝管
参考答案：A
My favourite photo _____ by my mother when I was two years old.[ ]
A. takes
B. is taken
C. took
D. was taken
遥测变送器的精度应不小于（）。
A.1级
B.0.5级
C.0.2级
D.0.1级
