We missed our train, and ___ the next train was delayed, ____ we had to wait for two hours.
| A．on top of that; in that case | B．as a result; so that |
| C．because; therefore | D．what was worse; in which case |
_____, water can be changed into gas.
| A．Heated | B．Being heated |
| C．Having heated | D．Having been heated |
There is _____ what the weather will be like.
| A．not knowing | B．no knowing | C．not know | D．no known |
I am too glad _____ you.
| A．to see | B．seeing | C．saw | D．at seeing |
The Arctic is considered _____ the northern part of the Atlantic.
| A．having been | B．to have been | C．to be | D．being |
_____, the boy couldn't enter his house.
| A．Since the key had lost | B．The key being lost |
| C．Lost the key | D．Having lost the key |