脲原体与支原体主要的区别在于脲原体()
A.能水解尿素
B.含有DNA、RNA两种核酸
C.在光镜下可观察其形态
D.为致呼吸道感染的病原体
E.青霉素治疗无效
参考答案:A
.During the test we were supposed to stay in our seats , keep our eyes on our work , ___________to anyone .
A.but could not talk
B.instead of speaking
C.rather than speak
D.and not speak
A.小明在前50m一定用了6.25s
B.小明每秒钟通过的路程都是8m
C.小明的平均速度是8m/s
D.小明的平均速度是8km/h