The famous star got injured in a traffic accident before her concert ,______ made her fans worried.
| A．who | B．as | C．what | D．which |
Everyone in our class was working hard and doing what we could ________ a good university.
| A．enter | B．to enter | C．entering | D．entered |
QQ, ________ you can chat with your friends, makes communication easy.
| A．how | B．where | C．that | D．which |
I was watching the news on TV ________ the power went off.
| A．when | B．as | C．while | D．until ． |
—How long will it be ________ the 30th Olympic Games is held in London?
—It won’t be two years, I think.
| A．when | B．that | C．before | D．since |
When first ________ to the market, the computer software ． was not a success due to its complexity in operation.
| A．introducing | B．being introduced | C．introduced | D．to be introduced |