see if (someone) can (do something)

To "see if" you can do something means to try to do it. After you try, you will "see" if you were successful or not. You can use "see if ___" like this:

I'm going to see if I can change my appointment to the following day.

Let's see if we can find somewhere to park.

a pit

A "pit" is a deep hole in the ground. Imagine a hole that's deeper than a person's height.

Pits don't show up in real life that often, but you can see them sometimes in T.V. shows and video games.

grab the ledge (of something)

A "ledge" is the sharp top edge of something like a building or a rocky cliff.

When someone falls or slides off of something high up, they might "grab the ledge" to save themself.

I slipped and started to slide down the face of the mountain, but luckily I was able to grab a ledge and hold on.