Several minutes after its launch, the X-37B plane successfully sent back its first___________to the control center.
— Michael was late for Mr Smith's oral class this morning, —_________? As far as I know, he never came late for class.
It's the sort of work that _________ a high level of concentration.
He spoke for quite a long time, but he threw no _________ on themain point.
I have many friends, some _________ are businessmen.
_________ its low cost, the appeal of iron as a building material layin its strength, its resistance to fire, and its potential to span vastareas.