给朋友打气，让他们感到振奋和鼓舞，是我们作为朋友的职责和责任。以下是一些简短的英文句子，可以用来鼓励和激励我们的朋友：

1. Believe in yourself and you will achieve great things. 相信自己，你将会取得巨大的成就。

2. Keep pushing forward and never give up. 继续向前，永不放弃。

3. You are capable of amazing things, so go out there and make it happen. 你有惊人的才能，所以走出去，让它发生。

4. Don't be afraid to take risks and try new things. 不要害怕冒险和尝试新事物。

5. Remember that failure is just a stepping stone to success. 记住失败只是通向成功的垫脚石。

6. Believe in your dreams and make them a reality. 相信你的梦想，让它们成为现实。

7. Never let anyone else's opinions define who you are or what you can achieve. 永远不要让别人的意见定义你是谁或者你能达到什么。

8. You are stronger than you think, so keep pushing through the tough times. 你比你想象的更强大，所以坚持度过难关。

9. Don't give up on yourself, because I believe in you. 不要放弃自己，因为我相信你。

10. Every obstacle you overcome brings you one step closer to your goals. 每一个你克服的障碍都让你离目标更近一步。