What a fast running boy (he is)?和What a fast boy he is running?怎么改成陈述句?(请说出过程)

问题描述:

What a fast running boy (he is)?和What a fast boy he is running?怎么改成陈述句?(请说出过程)

He is a fast running boy.把what 去掉,把he is 放到最前面.
第二句是错句,没那么说的