初三英语单选题【求原因求解释!

问题描述:

初三英语单选题【求原因求解释!
By singing English songs,( )
A he improved his speaking skill
B his speaking skill was improved
C his spoken skill was improved
D he improved his spoken skill

A 首先speaking skill意为表达技巧因此排除C,D
然后看A的主语为he B的主语为skill 介词by的前后主语应当一致
应该是he singing songs ,所以选A
个人是这么认为的