对早期食管癌,简单易行的确诊方法是
A.X线钡餐检查B.食管镜检查C.带网气囊食管脱落细胞检查D.CT
参考答案:C
The girl looked at me with a _______expression. Maybe the problem was quite ______.
A.puzzled; puzzling
B.puzzling; puzzled
C.puzzled; puzzled
D.puzzling; puzzling
作出下列杠杆所受各力的力臂。