简述汽车美容的原则。
参考答案:
1)预防与治理相结合的原则
2)车主护理与专业护理相结合的原则
3)单项护理与全套护理相结合的原则
4)局部护理与全车护理相结合的原则
若圆x2+y2=4与圆x2+(y-3)2=r2 (r>0)外切,则实数r的值为______.
Would you mind _____ early tomorrow morning?[ ]
A. getting up
B. to get up
C. got up
D. to getting up