they can catch the train. It's a question.合并成一句. It's a question whether they can catch the train _______ _______.还请说明为什么怎么填?

问题描述:

they can catch the train. It's a question.
合并成一句.
It's a question whether they can catch the train _______ _______.
还请说明为什么怎么填?

It's a question whether they can catch the train or not.

or not

on time 准时
他们是否能准时登上火车,这是个问题。

OR NOT

填or not.whether...or not是固定搭配

in time
他们能否及时的赶上火车还是个问题
翻译过来就明白了