名词内衣，背心，汗衫

1. 汗衫：undersea lightwave cable 海底光缆 | undershirt 汗衫 | undershorts 松紧短衬裤

2. 汗衫,汗背心,贴身内衣：underpants 内衣裤 | undershirt 汗衫,汗背心,贴身内衣 | urethra 尿道

3. 衬裙：2 裙子 shirt | 衬裙 undershirt | 百褶裙 pleated shirt

1. 贴身内衣；汗衫；背心
An undershirt is a piece of clothing that you wear on the top half of your body next to your skin in order to keep warm.

e.g. He put on a pair of short pants and an undershirt.
他穿上了一条短裤和一件汗衫。