单项选择题
A.is B.are C.was D.were
Mary told me that she（）to the supermarket before coming...
单项选择题Mary told me that she（）to the supermarket before coming home
A.went B.had gone C.has gone D.goes
Many people watched the boys（）the mountain at that time...
单项选择题Many people watched the boys（）the mountain at that time.
A.climb B.climbing C.to climb D.climbed
Many countries are increasing their use of natural gas,...
单项选择题Many countries are increasing their use of natural gas, wind and other forms of （）
A.energy B.source C.power D.material
