Finally, I need to prepare for the Olympic math contest next year. I can't let someone down who always care me.

最后，我要为明年的奥林匹克数学竞赛准备。我不能让关心我的人失望。

youdao

Find someone who will let you talk things through, or failing that, write down your thoughts.

找个能让你畅所欲言的人，如果不能的话，就把你的想法写下来。

《柯林斯英汉双解大词典》

Let go. If you need to vent, talk with someone or write your feelings down on a piece of paper and then throw it away.

放手。若你需要宣泄，就找人倾诉或是将你的感受写在一张纸条上，然后扔了它。

youdao

"I think that is very much a sign of someone's teenage years because in order to be truly joyful you have to let your barriers fall down, " he argued.

BBC: Newsbeat - Music - Mika pens 'teenage' second album