用英语安慰心情不好的人时，你可以采用以下几种方法：

1. 表达同情和理解：

"I'm really sorry to hear that you're feeling down. I can imagine how tough it must be for you."

"It sounds like you're going through a hard time. I'm here for you."

2. 倾听和支持：

"You can talk to me about it. I'm all ears."

"It's okay to feel this way. You're not alone in this."

3. 给予实际帮助：

"Is there anything specific I can do to help you feel better?"

"Let's find a way to tackle this together. Maybe we can go for a walk or grab a coffee?"

4. 正面鼓励：

"You've been through a lot, and you've shown so much strength. I believe in your ability to get through this."

"Remember, this too shall pass. It's important to take a moment for yourself."

5. 分享正面信息：

"I know things seem tough now, but they always have a way of working out in the end."

"It's amazing how resilient we are as humans. You've got this!"

6. 转移注意力：

"Why don't we focus on something fun? Maybe we can watch a movie or read a book together."

"Let's go for a drive and take in the scenery. Sometimes a change of environment can help."

7. 提醒对方的优势：

"You have so many wonderful qualities. You're an amazing person, and I'm glad to have you in my life."

"You've faced many challenges before and have always come out stronger. This is no different."

记住，每个人的情况都不同，所以在安慰别人的时候，要尽量根据对方的感受和需求来调整你的话语。