It happened one spring morning. I woke up and went downstairs. My mum asked me if I wanted some orange juice.

    “Yes, thanks,” I replied, but my voice had changed! It sounded very deep. I was quite1 and so was the dog! But my mum just smiled and said, “Oh, that's just your voice breaking.”

    Breaking? That did not sound good! So at school that day, I asked my biology teacher what was happening.

    “Don't worry. It's2 common!” she said. “Sound is made by the mouth as the air is 3 out through the voice box, which is in the neck. As you grow older, the voice box grows larger and thicker. When you are a teenager, there can be a 4.

    “But my sister is older than me, and her voice is still the same,” I said, a little 5.

    “The change is bigger in boys, so you notice it more. Girls' voices only change a little, so it is hard to tell the6.

Now I like my new voice. But the dog still is not sure!