这是两个句子,其同义句可以把它合成一个包含宾语从句的复合句,We can ask him what he often does.宾语从句应该用陈述语序的句子,而What does he often do 是疑问语序,因此,应去掉助动词does ,然后把谓语动词do变为单三形式does.