单选题：—Why didn't you pay the bill for Tina?—I offered to, _____..

—It’s a long time________I saw you last.—Yes, and what a pity it is now that it will be a long time________we see each other again.[ ]A. before; sinceB. since; whenC. since; beforeD. when; before

He supposed he'd be late for the film The King's Speech ______ he ended up getting there ahead of time.[ ]A. butB. orC. soD. for

Turn the heat down ________ your cake will burn.[ ]A．and B．orC．soD．but

I have a tight budget for the trip, so I'm not going to fly _the airlines lower ticket prices.[ ]A. onceB. if C. afterD. unless

He shut the window with such force ________ the glass broke. [ ]A. whichB. thatC. as D. when