Lee was faced with the of whether or not to return to his country after he got the doctor's degree in America
The drug used to treat this disease causes bad side effects, some of which ________ deadly.
.No sooner ________ down on bed ________ the telephone rang.
________ about wild plants that they decided to make a trip to Madagascar for further research.
Fighting an artificial greenhouse effect seems to be the greatest of environmental challenges, ________?
A series of stimulus policies and supportive measures taken by the government ________ to promote change in the economic environment in this area.