

以前、この店に来たことがあります。
以前より日本語が上手になりましたね。
以前はたばこを吸っていましたが、今はやめました。
"いぜん(以前)" is in the lesson "Time 2" (Level 35), along with 11 other useful words. LinDuo has 180 topic lessons like this one, 2,379 words in total. Every word has an illustration, a transcription and pronunciation in a female and a male voice. Just 10–15 minutes a day is enough to learn them all. Free, and works offline.