粒子移动方向是（）
A.直线的方向
B.与平面平行的方向
C.与面垂直的线的方向
D.以上说法都不正确
参考答案：C
简述面部整形手术切口线的设计原则。
She couldn't help, even though she tried not to,（）at the strange clothes her friend was wearing.
A. to laugh
B. laugh
C. laughing
D. laughed
