

暗くて鍵を開けることができません。
誰が部屋の鍵を開けるの?
朝、店の鍵を開けるのは私の仕事です。
"かぎをあける(鍵を開ける)" is in the lesson "Verbs 11" (Level 23), 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.