读一读，猜一猜。
      They are twin brothers (孪生兄弟). One is on the right and one is on the left. But they have never
seen each other (从未见过对方).
What are they? They are ______________.

参考答案：
ears
答案不唯一

读一读，猜一猜。
      They are twin brothers (孪生兄弟). One is on the right and one is on the left. But they have never
seen each other (从未见过对方).
What are they? They are ______________.

参考答案：
ears
答案不唯一