

犬が私の横で寝ています。
母の横で料理を手伝います。
だれの横で写真をとりましたか。
"よこで(横で)" is in the lesson "Adverbs 1" (Level 23), along with 15 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.