Every modal verb is a bit different and not all of them can be used in all tenses. We use "may" for permission, but we can use "can" and its conditional form "could" as well.

A relaxing bobcat family is surprised by the appearance of a young black bear. Elsewhere, a raven family is threatened by the presence of a bald eagle circling above their nesting site.

In the wooded valley, a pine squirrel falls prey to the voracious bobcat. Here we find some of the oldest and tallest trees on earth: The giant sequoias, which are now a major attraction for visitors to the park.

Tommy’s former associate is determined to recruit him, but his sister is against it, and shows Tommy something that she thinks might convince him to stay on the straight and narrow. Then a surprise sighting at the burger restaurant reveals that she has been misleading him about somebody close to his heart.

Modal verbs are special verbs that go together with action verbs to indicate ability, permission, obligation and more. Let's see how they work.

After a decade of success in the music industry, American singer Miley Cyrus looks back at her past and the way she used to be with this introspective track from her eighth studio album, Endless Summer Vacation.

Enigmatic Smiths frontman Morrissey and rock star David Bowie clearly enjoyed their duet on this live version of "Cosmic Dancer," which they performed as an encore after an LA concert. The song was written by Marc Bolen of the English glam rock band T-Rex.

Tommy has his first day at a very boring job that his parole officer set him up with. On the way home to his sister's house, he finds himself face to face with some old acquaintances.

As spring arrives, the remarkable and deadly poisonous Sierra newt moves to its traditional aquatic breeding grounds. Meanwhile, kingfishers fish the crystal clear Yosemite streams and squirrels play a dangerous game of chase with the hunting bobcats.

Molten granite was cooled and scoured by glaciers, forming Yosemite’s almost surreal landscape with its many remarkable rock formations. Black bears inhabit the park and emerge each spring from their hibernation, ready to begin a new cycle of life.

Ed reminisces fondly in a song about the time he spent living in the United States, and an English girl that he spent time with.

Tommy’s sister, Viki, is taking a very active role in controlling his new life outside of prison. In his meeting with a new probation officer, he immediately makes a bad impression before promising her that he's determined to get his life back on track.

“Because We Can” is about tension in a relationship that has lost its way, but there's a determination to turn things around and make it work again. The song features on Bon Jovi’s twelfth studio album, What About Now.

Audio and video sources can be factual, and can be used as evidence, but they can both be doctored, too. When we don't have the facts, we might have hearsay, but can we trust it?

Tommy heads off to a place that holds special memories for him. Later on, his prison habits make fitting into a family meal difficult, and his sister sends away his first visitor from the past.