ThekeytotheindustrializationofspaceistheU.S.spaceshuttle.______it,astronautswillbeabletoflyintospaceandreturningmanytimes.
A.With B.By C.On D.In正确答案A
ThekeytotheindustrializationofspaceistheU.S.spaceshuttle.______it,astronautswillbeabletoflyintospaceandreturningmanytimes.
A.With B.By C.On D.In正确答案A