

夜になると咳をすることが多いです。
まだ咳をするの?薬、飲んだ?
咳をする時は、口を手でおさえてください。
"せきをする(咳をする)" is in the lesson "Sickness" (Level 9), along with 17 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.