The president was _____ a speech to senators _____ a group of armed young people burst into the hall. [ ]

__ astronauts cannot go to a baseball game or amovie in orbit , there are many familiar activities that they can still enjoy

Is this eraser __________ –No, it’s not ________. It’s Jim’s.

下列各句中，表达得体的一句是

ouldn’t agree to sell the house to us at thesame price _____ they had promised, _____ was rather disappointing.