诊断肠套叠的首选方法是()
A.B超
B.CT
C.碘水造影
D.钡剂或空气灌肠
E.MRI
参考答案:D
---- How much does it _______ to fly from Beijing to Haikou one-way?
---About 1000 yuan.
A.cost
B.pay
C.spend
D.take
化合物NO2的名称是( )
A.一氮化二氧
B.氮氧二
C.二氧化氮
D.氧化二氮