If he takes on this work, he will have no choice but ______ an even greater challenge.
He is really a friend of mine. He would _______his last penny with me.
The Smiths are going ______ separate holiday ___________.
you had better drop your parents a ________ in case (以防)they are worrying about you.
If you are left _______ on a _________land, how will tou make a living?
He studies in the evening instead ________ the day.