DDM

例句：

1. 1. The cell membrane is made up of two layers of lipids.
   细胞膜由两层脂质组成。
2. 2. The double-layered structure provides excellent protection against water loss.
   双层结构提供了极好的防止水分流失的保护。
3. 3. The protein molecules are arranged in a double-layered pattern within the membrane.
   蛋白质分子在膜内以双层排列的模式存在。