you guys

People use "you guys" when talking to a group of people that may include men and women. For example, a waiter might say this to a large family eating at a restaurant:

Have you guys been here before?

English has a problem because "you" is used for both one person and a group of people. It can be confusing. To fix this, people in different regions use different words to talk to a group. In Southern areas of the U.S., some people say "y'all":

Have y'all covered exponents yet?

People in other areas of the country think this sounds really dumb, though.

"You guys" is still considered casual English, but it's very common for younger people and people from the West Coast of the U.S. to use this phrase.

cover (something)

In a class, you "cover" different topics. That means that the teacher teaches them:

We covered the French Revolution last time.

In a meeting, you "cover" items that need to be discussed:

We have a lot to cover today. Let's get started.

News reporters also "cover" news stories.

Why does the news insist on covering these silly celebrity scandals?

In all of these cases, "covering" something means discussing things that are on a list of things to talk about.

exponents

Exponents are a topic in mathematics.

An exponent is something like 2² or 3⁵ or 10^x. You multiply the big number by itself the number of times shown in the small number (the exponent):

3⁵ = 3 x 3 x 3 x 3 x 3

When you're reading an exponent out loud, you say:

"Two squared" (2²)

"Eight cubed" (8³)

"X to the Y power" (x^y)