Hear or listen (to)?

‘Hearing’ is an event; it is something which happens to us as a natural process. ‘Listening’ is an action; it is something we do consciously.

Compare

hearing is an event.	listening is an action.
Suddenly I *heard* a noise. Someone was in the garden.Did you *hear* the thunder last night?[on the phone]The line is very bad. I can’t *hear* you.	I *listened* very carefully to what she said and wrote it all down.Do you *listen to* the radio in bed?George! *Listen to* me! I have something important to tell you.

Sometimes we can use either hear or listen to, depending on whether we want to emphasise the event or the action:

Did you hear that interview with David Beckham on the radio yesterday? (emphasis on the event)
Did you listen to that interview with David Beckham on the radio yesterday? (emphasis on the action)
I love hearing/listening to the sound of falling rain.

We don’t normally use hear in the continuous form. We often use hear with can:

warning

We use to after listen before an object:

Every morning I listen to my Mozart CD while I’m having breakfast. It prepares me mentally for the day.
Not: ~~Every morning I listen my Mozart CD~~ …

We use listen without to if we do not mention the object, or if it is a discourse marker:

Meena, listen! I don’t want you staying out late!
Listen*, I was wondering if you could help me.* (discourse marker beginning a new topic or phase of a conversation)
The music was beautiful. We just sat there and listened.