The last time we had great fun was ________ we were visiting the Water Park.
To get a better grade, you should __________ the notes again beforethe test.
The World Expo is like __________ great stage for cultural exchange, bringing people into closer contact with __________ rest of the world.
__________ without friends __________ the most difficult challenge for Chuck while living on the island.
The new plane will __________ a series of test flights before it is put into use.
In April, thousands of holidaymakers remained __________ abroad due to the volcanic ash cloud.