---That must be a mistake. ---No, it ___ a mistake.
Every member tries their best to finish the important work, ______ they aren’t permitted to go home on time.
______ all of them are strong candidates, only one will be chosen for the post.
When asked about their opinions about the schoolmaster, many teachers would prefer to see him step aside ______ younger men.
Let’s learn to use the problem we are facing ________ a stepping-stone to future success.
—Would you like to join me for a quick lunch before class?— ______, but I promised Nancy to go out with her.