大小齿轮的齿数比是8:3,大齿轮比小齿轮多15个齿,小齿轮有[ ]
A.3个齿
B.6个齿
C.9个齿
D.12个齿
答案:C
What time do you usually _____ in the morning? [ ]
A. have a breakfast
B. have breakfast
C. have the breakfast
D. have breakfasts
从事放射工作满20年的在岗放射工作人员,可以收所在单位利用休假时间安排健康疗养。