I was so familiar with her that I recognized her voice ______ I picked up the phone. [ ]

circumstances ________ our control, theperformance has to be canceled

It is already 10 o’clock. I wonder how it ______ thatshe was two hours later on such a short trip.

I hear Tim is leaving. –_________ why

Much of the power of the trade unions has been lost ____, their political influence should be very great[ ]