There are a great number of natural resources in the desert, which remain to be ________.
The manager of the sales department is kept busy all day. After he has solved one problem, another is sure to _______.
----- Have you ever visited the 2010 Shanghai World Expo? -----Yes.When I was in China , I ______ it twice.
The old lady ______ the shopkeeper of charging her too much for the goods she had bought.
I can’t imagine how he finished the relay race, ______ his foot wounded so seriously.
Dear me! Just _____ at the time! I _____ no idea it was so late.