根据decide可以排除AC,不能用to
根据语序,D也错
选B那decide to do sth是什么时候用？VERB决定，拿定主意（做）If you decide to do something, you choose to do it, usually after you have thought carefully about the other possibilities. 这里是宾语从句，不一样的，decide to do 这个搭配有的,这里出现了特殊句式，搭配就不存在了