对称是我国造型艺术传统的风格之一，这种审美习惯反映到服装上，以下列那种服装为代表（）。
A.茄克衫
B.礼服
C.连衣裙
D.中山装
参考答案：D
He works as an engineer now, but he________ on a farm for three years.[ ]
A. has worked
B. worked
C. was working
D. had worked
表示流体之间内摩擦力大小的物理指标称为（）。
