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
