Shanghai is the first city in the world ____a high-speed maglev train, from the city to Pudong Airport.
| A．to build | B．to be built | C．to have built | D．to have been built |
He was about to tell me the secret ______ someone patted him on the shoulder.
| A．as | B．until |
| C．when | D．while |
I was about to go out ______ the telephone rang.
| A．when | B．suddenly |
| C．as soon as | D．directly |
We were swimming in the lake _______ the storm started.
| A．when | B．suddenly |
| C．until | D．before |
She was walking down the road _______ she heard someone shouting for help.
| A．when | B．suddenly |
| C．until | D．before |
The fire went on for quite some time _______ it was brought under control.
| A．when | B．since |
| C．after | D．before |