Question

you will ()if you use a computer

（）easily you will find it to use the computer if you know the function
A how B how a C what D what an

Answer 1

（A、How） easily you will find it to use the computer if you know the function!
如果你知道这个功能,你会发现使用电脑是多么的容易!
这个感叹句的中心词是副词easily,所以感叹词要用how.