A lot of people toss them into nearly every sentence without thinking. Not only will this make your writing sound weak and equivocating, but it will make your very thought processes sound that way. When you strike these words from your writing, you'll find you have to think harder about what you're trying to say, and this is good. If you don't know, you're not ready to write this sentence. We found relatively few Early Woodland sherds at this site.
Adverbs are often meaningless, particularly the ones listed above.
They usually weaken your writing, rather than strengthen it. It should act as an intensifier, but if often has the opposite effect. Whenever you write this word, try striking it out and see if it doesn't make the sentence stronger. Now you know why this is a bad paragraph, and how you could fix it.