undershirt under vest

例句：

1. 1. I need to change into my undershirt before I go to bed.
   我需要在上床睡觉前换掉我的内衣。
2. 2.The undershirt is made from cotton and has a soft texture.
   这件内衣是用棉制成的，质地柔软。
3. 3. He wore an undershirt under his shirt for warmth.
   他穿着一件内衣在衬衫下保暖。