Yosemite’s trees and animals have adapted to endure the occasional wildfire and the extreme changing of the seasons. In September, marmots prepare their burrows for hibernation and the deer are full of energy as the annual rut approaches.

Now Sigrid has also lost her glasses! In this final part, learn how to use modal verbs to express probability, and find out whether she finds the missing items.

In the lower valley, a foraging black bear attacks a colony of ants, which quickly rally to defend themselves. At its driest in summer and fall, the park is at the mercy of forest fires. One of the largest ever, the Rim Fire, broke out in the autumn of 2013, and burned out of control for over ten weeks.

Sigrid has lost a couple of important items and is trying to think where they might be. In this part, she has lost her car key. She uses plenty of modal verbs to tell her story, including modal verbs expressing probability.

It’s June, and Yosemite has come alive with noise and vibrant colors. The meadow flowers are in bloom, the bobcat kittens are almost full-grown, and the park’s unique amphibian and rodent populations emerge from their winter rest.

When do we use "should" and "could"? At the end of the video, you'll also find a preview of the next 2 videos where modals are used in everyday speech for discussing probability.

The imposing rock faces of Yosemite are very popular with sport climbers, and the rocky heights are also home to the endearing American pika. Mule deer, many with fawns, inhabit the lower valley, which is awash with spring color.

Kate lives in Grand Lake, Colorado, a small town that is considered the gateway to Rocky Mountain National Park. Kate’s friend Tom is inspired by the cold and recent snow to go out and take a plunge in the icy lake!

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.

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

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.

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?