英语,直接引语变间接引语时,把say变成tell、ask或者order时有什么区别吗,该怎么变

有些区别,口气不同例如,My father said to me,"I read the book in 2006." 改为 My father told me he read the book in 2006.若是 祈使句则更明显.例如,'Piease explain why you're two and a harf hours late," the boss said.改为 The boss asked him to explain why he was ...……那应该怎么区分啊一般的用 tell,口气重的分情景用ask,order.