请将下列句子中的错误改正过来。
It's very nice for you to say so.
A bike runs much more slowly than a motorbike.
The child began to learn to play the piano until he was eleven.
參考答案:It's very nice of you to say so.
A bike runs much more slowly than a motorbike does.
The child didn't begin to learn to play the piano until he was eleven