When a space shuttle has accomplished its _____, it can be ready for another trip in about two weeks.
Until today we have reached a stage ______ we have almost no rights at all..
I invited Joe and Linda to dinner, but ________ of them came.
Only when he is seriously ill ______ in hospital.
I would advise you there by bus, because it’s too crowded.
The reason I’m writing to you is to tell you about a party on Saturday.