I don’tknow who invented ________ telephone It’s really ________ most usefulinvention

Even though they are not doubtful at all _______ John will pass the exam, I still wonder ______ he is fully prepared

Who is Clarke? —_____ him yet? I saw you shaking hands with him at the meeting

___ difficult and challenging thetask may be, we must finish it on time, because there is a possibility _________we’llbe fired if we can’t fulfill the task on time．

You ______ things aboutLook, what a mess in your room!