you can use both of sentence are ; 1. during the time that something is happening 2. at the same time as something else is happening such as You can go swimming while I'm having lunch. shoes mended while you wait 3. used to contrast two things While Tom's very good at science, his brother is absolutely hopeless. Some people work better to music while others do not. 4.(used at the beginning of a sentence) although; despite the fact that… While I am willing to help, I do not have much time available. Cheer,