动脉血PaCO2的参考值范围是
A.45~55mmHg
B.30~40mmHg
C.45~50mmHg
D.35~45mmHg
E.35~40mmHg
参考答案:D
麻疹主要通过何种途径进行传播:()
A.空气飞沫
B.皮肤接触
C.血液
D.消化道
E.污染器具
When Lily came home at 5 p.m. yesterday, her mother()dinner in the kitchen.
A.cooked
B.was cooking
C.cooks
D.has cooked