awhile
For a short time.
Awhile means for a short period of time. When your mom says “wait awhile,” she's asking you to be patient for a bit. When you've been reading awhile, you've been at it for some time, though not necessarily hours.
The tricky part: awhile is actually different from a while, even though they sound identical. Awhile is an adverb that modifies a verb, so you'd write “let's rest awhile” (describing how long you'll rest). But when you need a noun with an article, you write it as two words: “let's rest for a while.” An easy test: if you can put “for” or “in” before it, use two words. You can say “for a while” but not “for awhile.”
Most people mix these up, even adults, so don't worry if it takes practice. The important thing is understanding that awhile means a temporary span of time. When your teacher says the class will work quietly awhile, she means you'll have some time to focus, but eventually something else will happen. It suggests patience and temporary waiting, not forever.