---Do you know who invented ________ telephone?
---No. But it is really________ most important invention.
| A．/; the | B．the ;/ | C．/ ;a | D．the ;a |
Look out! That tree _____ fall down.
| A．is going to | B．will be | C．shall | D．would |
Everyone likes to live in a house ______ windows face the south.
| A．whose | B．which | C．its | D．and which |
They talked about the persons and things ______ they remembered at school.
| A．which | B．who | C．that | D．whom |
His English teacher is a young girl, ____ left college only last year.
| A．who | B．where | C．which | D．as |
This is the factory ______ I visited last week.
| A．what | B．which | C．where | D．it |