小弟在一本书上看到这一句话,可否请哪位强者帮我分析一下里面的句型结构？
以下若有括号的部分是小弟自己的想法 有错还请指正
But (what the IPad is doing) is starting a new shift in the paradigm
of user interfaces, and (what it's going to be doing) is simplifying
computing for everyone so we don't have to deal with all these technicalities.
我想请问的地方是 为何需要写成what it's going to be doing呢？
而不是写what it's going to do
写成to be doing是有什么文意或文法上需要吗