限り
Usage
X限り is used when something is the case or is true as long as the condition X holds true. 限り is also used to indicate the extent to which one can do something or one knows something.
Examples
私の知っている限り、外国人が使いやすい日本語の辞書はないんですよ。
As far as I know, there isn't a Japanese dictionary that's easy for foreigners to use.
明日までにこのレポートを翻訳するのは結構大変ですが、出来る限り頑張ってみます。
It's quite challenging to translate this report by tomorrow, but I'll do my best as much as I can.