Aluminum isn’t found free in nature, owing to its always ____ with other elements, most commonly with oxygen.
| A．being combined | B．having combined |
| C．combine | D．combined |
He lost his favorite watch, _________ made him very sad.
| A．that | B．it | C．which | D．as |
I’m going to see what Dad is________. Two hours is a long time to take over a coffee.
| A．up | B．up to | C．up against | D．up with |
Professor Li is the person to ____________ you should write.
| A．whom | B．who | C．which | D．whose |
Do you know the reason _______ he was late?
| A．that | B．which | C．where | D．why |
I’ll take you to the museum ______ you may see everything _________ you want.
| A．which; that | B．where; that |
| C．in which; which | D．where; what |