首次实现了人类环绕地球一周的航行,从而证实了地球是一个球体的航海家是 [ ]
A、郑和
B、麦哲伦
C、哥伦布
D、加加林
答案:B
Eric nearly always wins the science award.That’s because his projects are ___.
A.extremely presented well
B.well presented extremely
C.presented well extremely
D.extremely well presented
导致患者内源性感染的因素包括
A.医院内有大量的病原体B.大量长期滥用抗生素C.腹腔穿刺D.消毒隔离措施不到位E.医疗器械污染