用（）可使眉型较自然。
A.眉刷
B.眉笔
C.眉粉
D.眉钳
参考答案：C
慢性呼衰失代偿期给氧的原则是：O浓度25％～30％，O流量1～2L／min，持续给氧。
— Can I have _____________ envelope and some _____________?
— Sure, here you are.[ ]
A. an; writing paper
B. a; writing papers
C. a; writing paper
