It was not until he became very ill ______ he went to see a doctor.
He was seriously injured.He lay on the ground, _______ to stand up.
---Thanks for your help, but can you do me one more favor, please?---____ , sir. What’s it then?
He is a man of few words, and seldom speaks until _______ to.
-- May I smoke here?-- If you____, that's the smoking section over there.
---How do you find James Cameron's 3D version of Titanic?---Fantastic! It can't be _______ and has brought us a wonderful experience.