-- The math problem _________ is not difficult. --- But after several tries , I have to give up _________ on it .
We will have a picnic if it _____ tomorrow.
Jim, dad asks you _____ down the TV. Mom is sleeping now.
—Must I return the book to you now, Jack? —No, you _____. You can give me back tomorrow.
He is poor _____ he is happy all the time.
—_____ does your mother go to work every morning? —At eight o’clock.