

あの二人は双子なので、顔がよく似ています。
双子の兄弟がいるって本当ですか。
隣の家に双子の赤ちゃんが生まれたそうです。
"ふたご(双子)" is in the lesson "Family 1" (Level 1), along with 12 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.