That boy decided______in class any more A not taik B to not

这个应该选C.decide的具体用法如下：
decide vi., vt. 决定；断定；判定
[用法]1. decide to do：Last week, a group of Class 3 students decided to go to the museum in the centre of the town. 上星期,三班的一些学生决定到位于镇中心的博物馆去.
2. decide that...：When the winds started to get strong, the family decided that it was not safe to remain in the house. 当风势开始加强的时候,这家人认定,继续呆在房子里是不安全的.
3. decide + 疑问词 + to do：We must decide which one to buy. 我们一定要定下来究竟买哪一个.
4. It is decided that...：It is decided that we should start tomorrow. 已经决定我们明日出发.（注：这种从句要用虚拟语气.）

C
decide to do sth是肯定形式，意思是决定做某事。decide not to do sth 否定形式，意思是决定不做某事

选C 因为 decide的用法是decide to do sth 而 不定式的否定直接在to前加not

选C

C
decide to do sth 肯定形式，意思是决定做某事。
decide not to do sth 否定形式，意思是决定不做某事

That boy decided______in class any more A not taik B to not talking C not to talk D not talking
选C，not to talk
这个男孩觉得不再在课堂上讲话。
decide to决定做某事
decide not to决定不做某事。

C

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选C，因为有固定搭配decide to do sth. 意为决定做某事和decide not to do sth. 不决定做某事，根据题意，应为，“那个男孩再也不准备在课堂上说话了”，所以选C。
另外，以后见到decide一词，肯定用decide to do sth.否定用decide not to do sth. 就行了。~(≧▽≦)/~
注:sth....