语风汉语

“预订”和“预定”都表示预先把某件事情定下来，但具体用法有区别。

"预订" and "预定" both indicate that something has been decided beforehand, but the specific usage is different.

“预订”表示预先订购、订阅、订租等。例如：

(1)我昨天去食品店预订了一个蛋糕。
(2)明天是会议的闭幕式，他已经在饭店预订了两桌酒席。
(3)老李给咱们预订了3张飞机票。
(4)现在就可以去邮局预订明年的《参考消息》。
(5)你到附近的饭店给这几位客人预订5个房间。

"预订" means pre-ordering, subscribing, renting, etc. For example:

(1) I went to the grocery store yesterday and ordered a cake.

(2) Tomorrow is the closing ceremony of the meeting. He has booked two tables in the hotel.

(3) Lao Li booked us three air tickets.

(4) Now you can go to the post office and book next year's Reference News.

(5) You go to a nearby hotel and reserve five rooms for these guests.

“预定”则表示预先规定或者约定。例如：
(6)这项实验将在预定日期进行。
(7)直升机今天中午在灾区预定地点降落，接伤病员。
(8)还是按照预定方案开展这项工作吧。
(9)在这届运动会上，所有比赛项目都是按照预定程序进行的。
(10)今年在自主创新上获得新的突破，是我们的预定目标。

"预定" means pre-stipulation or agreement. For example:

(6) The experiment will be conducted on a scheduled date.

(7) The helicopter landed at the designated place in the disaster area at noon today to pick up the wounded and sick.

(8) Let's carry out this work according to the scheduled plan.

(9) In this Games, all the events are carried out according to the scheduled procedure.

(10) It is our target to achieve new breakthroughs in independent innovation this year.

从词语的关涉对象来说，“预订”一般关涉钱款交易，而“预定”则与时间、计划、方案、目标、地点等相联系。因此，您提到的“预定计划”的写法是规范的。

From the perspective of the target of words, "预订" is generally related to money transactions, while "预定" is related to time, plan, plan, goal, location, etc. Therefore, the formulation of the "scheduled plan" you mentioned is standard.

下面是错用的例子：

Here are some examples ofmisuse:

(11)这个旅游团本来预订星期二启程，后因天气原因，推迟了两天。(应用“预定”)
(12)本市邮局现在已经开始预定明年报刊。(应用“预订”)
(13)这件事预订下个月中旬开会研究。(应用“预定”)

(11) The tour group was scheduled to leave on Tuesday, but was delayed for two days due to weather. (Applying "预定")

(12) The City Post Office has now begun to book newspapers and periodicals for next year. (Apply 预订)

(13) The matter is scheduled for a meeting in the middle of next month. (Applying "预定")