what did the teacher tell them he hold them ____ in the street.横线上为什么用 not to play .为什么不能用don`t play

因为tell 的用法是tell sb to do sth 或者tell sb not to do sth

上面hold打错了，应该是told。
tell sb。（not）to do告诉某人（不要）做某事。是固定搭配。注意此处them是宾格。
如果用tell后面跟从句，them应该用主格，即：He told they didn't play in the street. 此处要用didn't play不能用don't play，宾语从句前后时态要一致。

he told them not to play in the street.
固定搭配 tell sb. not to do sth

tell sb not to do sth 是固定搭配

hold 应该是told,是tell的一般过去时
tell sb.to do sth
tell sb.not to do sth 告诉某人不要做某事