It is fairly common in Africa for there______ a group of expert musicians surrounded by others who also join in the performances.
Visitors can see the large diamond, ______ has been kept at the Tower since the 17th century.
—Sorry, I forgot to lock the door. —______ Mike can do it later.
—Do you know ____ made him successful in his career? —Yes. His hard work and determination, of course.
With many cities in China dreadfully blanketed by thick haze, the environment problem is _____ Chinese people concern most nowadays.
The doctor tried to laugh my brother ____ his fears about the coming operation.