Some scientists believe that it won’t be long _______ robots are widely used in all walks of life．
| A．since | B．after | C．before | D．until |
It shocked me to see ______ my neighbors treated their children.
| A．why | B．whether |
| C．how | D．since |
―When do we need to pay the balance ?
― September 30.
| A．In | B．By | C．During | D．Within |
There were a lot of people standing at the door and the small girl couldn’t get _______.
| A．between | B．through | C．across | D．beyond |
The kind-hearted couple decided to adopt the boy ____ parents had been killed in an accident.
| A．of whom | B．with whom | C．on whom | D．in whose |
As a lover of popular music, she enjoys listening to it _____ MP3.
| A． in | B．on | C．with | D．by |