s being the only one; single and isolated from others
s marked by dejection from being alone
a. 寂寞的
1. I often feel lonesome when my friends are not around.
当我的朋友不在身边时，我常常感到孤独。
2. The lonesome road stretched for miles without any signs of life.
那条孤独的道路延伸了好几英里，没有任何生机的迹象。
3. She wrote a letter to her family because she was feeling lonesome.
她给家人写了一封信，因为她感到孤独。