What a pity! I have only one ruler in my pencil case.______ you ______ he can borrow it.
—Do you know _____ ? I'm going to see him. —Sorry, I don't know.
Let’s ask Mr. Wang for ________ about the earthquake.
If you don’t know a word, you must in a dictionary.
is really hard them to climb Mount Huang.
You won't pass your exams________ you work harder.