苦

例句：

1. 1. I've been working hard for weeks, and it's still not enough to pay the bills.
   我努力工作了几周，但仍然不够支付账单。
2. 2. The journey was tough, but we persevered.
   旅程很艰难，但我们坚持下来了。
3. 3. The old man had a bittersweet memory of his past life.
   这位老人对过去的生活有着苦涩而甜蜜的回忆。