

新しいマットレスにしてから、よく眠れます。
このマットレスは少し硬すぎませんか。
週末、家具屋でマットレスを見るつもりです。
"マットレス" is in the lesson "Interior" (Level 22), 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.