(someone) is in a position of authority

A "position of authority" is a job or title that puts a person in control of other people. Some common positions of authority are:

• a boss or manager
• a teacher
• a political leader
• a military leader
• a doctor
• a police officer

have a responsibilty to (do something)

This means that you must do something because it is your job or your moral duty. You have to do this because people are relying on you:

As a parent, don't you have a responsibility to keep your children safe and healthy?

The example above uses the negative form: "a responsibility not to do something"

abuse (one's) authority

To "abuse" a power or a privilege means to use it to do bad, selfish things. In this case, it means to use your authority in ways that benefit you unfairly, or in ways that hurt other people. For example, here are some examples of people "abusing their authority":

• The admissions director for a university lets her nephew into the school, even though he didn't have good grades in high school.
• The head of a department makes his employees go out to get coffee for him in the morning.
• A junior high school soccer coach sometimes yells at the players until they cry.

that

In the example above, "that" is used to make it clear that the first "authority" and the second "authority" are the same thing.

People (do something)

Talk about general behavior that a lot of people share like this:

People don't like to be told what to do.

People like it when you ask them questions about themselves.