It snowed heavily for three days ____ and they were separated from the outside world.
| A．in the end | B．on end | C．by the end | D．at the end |
___ he will come is certain.
| A．What | B．That | C．Whether | D．If |
Is this the factory ___ you visited last year?
| A．the one | B．where | C．that | D．which |
__ was once regarded as impossible has come true.
| A．Who | B．Which | C．That | D．What |
I have no idea ___.
| A．that she has come | B．what she has come | C．that she comes | D．what she came |
The reason______ he gave for being absent from school was ______ he had to attend his sick mother at home.
| A．which; because | B．why; because | C．不填; that | D．why; that |