I have the main idea: can study anywhere. Explanation one: use any device can be far from school. Example one: rural students can study at a city university without moving, different from past.

Some explanation texts give you clear instructions on how to do something, for a specific purpose - for example, an instruction manual that explains how to build furniture.

It is also important to know that extreme test data is NOT boundary testing. Sometimes extreme data is referred to as ‘boundary testing’ but this is a little inaccurate. In the above example ...