在普种麻疹疫苗前我国儿童麻疹发病每隔一定年限发生一次较明显上升,这种现象是()
A.大流行
B.暴发
C.长期变异
D.周期性
E.季节性升高
参考答案:D
---So you gave her your phone?
---______, she said she’d return it to me when she could afford her own.
A.My pleasure
B.Not exactly
C.No doubt
D.All right
“各器官系统发育不平衡”指()。
A.脑的生长发育先快后慢
B.生殖系统先快后慢,以至减退
C.淋巴系统先快后慢,以至减退
D.肌肉系统与生殖系统至青春期发育明显增快
E.同一系统中各个器官发育不一致