不让自己变弱用英文怎么说

在英语中，不让自己变弱可以用英文表达为 "strengthen oneself" 或 "prevent oneself from becoming weaker". 这两个表达法都比较常见，都可以用来表示在身体、心理、情感或某些其他方面保持或提升自己的能力。

下面是一些例句：

I need to strengthen myself physically by exercising regularly and eating a healthy diet.
She used meditation and positive affirmations to strengthen herself mentally and emotionally.
He worked hard to strengthen himself academically, studying late into the night and seeking extra help from his teachers.

其中 "strengthen oneself" 和 "prevent oneself from becoming weaker" 都可以用来表示不让自己变弱的意思，但前者更多用来表示在身体、心理、情感或其他方面的能力上的提升，而后者则更多用来表示防止自己变弱的意思。