She clicked the video and an ad popped up

"The cat sat.

This sentence is grammatically correct, but Grammarly can help! It's short but wordy. A better way to write this is...

The silver, white tufted cat crouched it's legs and elegantly placed it's butt on the hardwood floor. "

All she wanted was to watch the sweet video the school posted of her brother. He just died. Darn Grammarly. Don't download it. It doesn't even help.

That was the only lesson she ever needed to learn.