By the way, Harry, Happy Birthday.

Dean was told by Parvati that...

Now, this one's been hurt bad by something.

But Harry's never traveled by Floo powder before, Mum.

Make way there, please. Let me by, madam. Thank you.

...by a dodge as pathetically dimwitted as an Aging Potion.

All students will be escorted to each lesson by a teacher.

Maybe you don't have to do this all by yourself, mate.

You've got dirt on your nose, by the way. Did you know?

Prophecies can only be retrieved by those about whom they are made.

...they will be the first to enter the maze, followed by Mr. Krum...

As an antidote to your ignorance, and on my desk, by Monday morning...

There she was, walking by. You know how I like it when they walk.

"All students will return to their house common rooms by 6:00 every evening."

There was a time detention would find you hanging by your thumbs in the dungeons.

But if it kills by looking people in the eye, why is it no one's dead?

As for monkshood and wolfsbane, they are the same plant, which also goes by the name of aconite.