正常情况下吸空气时,SaO2接近100%,PaO2接近()
A.20mmHg
B.40mmHg
C.60mmHg
D.80mmHg
E.100mmHg
参考答案:E
What about _____ for a walk after dinner?
A.go
B.goes
C.went
D.going
当下述________成立时,称X→→Y为平凡的多值依赖。
A.X包含于Y
B.X∩Y≠
C.X∩Y=
D.X→→Y且Z=