—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.
------ Kate and Lucy are twins. ------ Oh, I ______ why they looked so alike.
A lunar probe-Chang’e-2_______ as much as 2 tons was sent up into space on October12010.
------What will you do during the coming winter vocation? ------ I don’t know, but it’s about time ______ something.
As the crowd rushed towards the gate, several people got______.
_______, he doesn’t study well.