Remember ______ the book in time when you have finished _____ it .
There _____ a pen, two pencils on the desk.
—Lily, here are your pens. Please _____. —OK, Mom.
I don’t like physics ______ it’s too difficult for me.
—_____ do you _____ the book? —It’s very interesting.
—How long can I keep the books? —_____