呕血(haematemesis)
参考答案:
上消化道出血时,胃内或返流入胃内的血液经口腔呕出称为呕血。
Circus tigers, although they have been tamed, can _____ attack their trainer.
A.unexpectedly
B.deliberately
C.reluctantly
D.subsequently
普通水平仪的水准器上刻度值为()。
A.0.02mm/m
B.0.04mm/m
C.0.05mm/m
D.0.06mm/m