—Whose English book is this?
—It _______ be Lily’s, but I’m not sure.
might
can’t
must
Our teacher often keeps usclassroom every day,so we must keep our classroom .
I had useful umbrella when it rained.
Monday afternoon we rode bicycle to Georgetown.
-Do you know _________________ ? --Sorry , I don’t know .
—Tom , Don’t talk. _______ what you are doing. —Sorry, Mr. Li.