In my learning book Easy Steps to Chinese 4 textbook you can see the sentence:
在北京游览,乘坐什么交通工具比较方便。
For the first part of the sentence, 在北京游览 means "visiting/touring Beijing" but is this a shortcut of 你在北京游览的时候 or 你在北京游览时? Is there any difference between these three sentences? Could I say 在吃饭,我用筷子。 Any grammar reference?