The birds song was beautiful
A bibliography includes any source you use while writing an assignment. This could be websites, book titles, etc.
When the movie ends, what the oak tree does at the theater is that it leaves.
This is a pun supposed to have a humorous effect on the listener or the reader - usually, when a movie ends, people leave the theater. However, since this is a tree, and it's got leaves, you can understand the correlation between the two words.
