at times 可以表达 时不时地
sometimes 主要表达 有时
两者都可作状语,但at times 作表示时间、地点的状语是不能直接放在谓语动词前面或谓语动词与宾语之间的.
如以下例句：
Children_____ do too much in gardens,in shops or even in their own homes.(A some time B sometimes C some times D at times
答案是sometimes