InAugust1977,asatellitetogatherdataaboutthe10millionblackholeswhicharethoughttobeintheMilkyWay.
A.launched
B.waslaunched
C.hasbeenlaunched
D.islaunched
正确答案:B
InAugust1977,asatellitetogatherdataaboutthe10millionblackholeswhicharethoughttobeintheMilkyWay.
A.launched
B.waslaunched
C.hasbeenlaunched
D.islaunched
正确答案:B