单选题____ the boy is to&n

问题补充：

单选题____theboyistolearntotalk.A.How slowB.How slowlyC.What a slowD.What a slow way

答案：

A解析这是感叹句，还原为：The boy is slow to learn to talk和The boy is to learn to talk slowly语法上都没有什么错误，但根据语境和常识判断，前一句是正确的。