I think it important to learn English. 划线部分在句子中的成份是：[ ]

Dad, could I have an MP3 like this one ?—Sure, we can buy ________ one, but as good as this.

First, connect the monitor _______ the computer. [ ]

What class are you in? —I’m in Class Two _____ David and Helen. [ ]

What are the children going to do if it_________ next Saturday?