Mum prepares breakfast for us every morning, so she __________ early.

  I ________ hear the news very clearly since the noise outside is so loud.

I am not feeling myself today! We ____ have drunk that much beer last night. 

It has been announced that students         remain in their seats until all the papers have been collected.

—Listen! Is Mary singing in the next room?—No. It _______ be Mary．She has gone to Shanghai for an important meeting.