Please arrange a substitute speaker in case Mr. Lin cannot attend the conference.

請安排一位替代講者，以防林先生無法出席研討會。

The supplier offered a substitute product because the original model was out of stock.

由於原型號缺貨，供應商提供了替代產品。

A substitute flight was booked for passengers after the morning departure was canceled.

早班航班取消後，已為乘客預訂了替代班機。