She had just finished her homework ______ her mother asked her to practise playing the piano yesterday.
| A．when | B．while | C．after | D．since |
It is known to all that ____ computer was invented in the USA.
A. that B. / C. the D. one
You will be late _____ you leave immediately.
| A．unless | B．when | C．while | D．as |
. Don’t leave your keys in the car. Someone might steal ________ .
| A．one | B．that | C．this | D．it |
we can avoid _________ with rest and a balanced diet.
| A．ill | B．to get ill | C．getting ill | D．be ill |
Expo 2010 Shanghai China __________ on both ba{007}nks of the Huangpu River in the city of Shanghai, China, from May 1 to October 31, 2010.
| A．is being held | B．is holding | C．will hold | D．holds |