—Who____ it be that is knocking at the door?
—It ____ be Father, but I’m not sure.
| A．can; must | B．can; may | C．must; can | D．may; must |
With his work completed, the businessman stepped back to his seat, feeling pleased_____ he was a man of action.
| A．which | B．that | C．what | D．whether |
--- Could you do me a favour?
--- It depends on ______ it is.
| A．which | B．whichever | C．what | D．whatever |
Doris' success lies in the fact _________ she is co-operative and eager to learn from others.
| A．which | B．that | C．when | D．Why |
These shoes look very good. I wonder __________.
| A．how much cost they are | B．how much do they cost |
| C．how much they cost | D．how much are they cost |
He spoke proudly of his part in the game, without mentioning ________ his teammates had done.
| A．what | B．which | C．why | D．while |