— Alvin, are you coming with us?— I’d love to, but something unexpected _____. [ ]

Excuse me, where did you get the book—I borrowed it from the ________.

If prices rise too high, the government has to dosomething __________ it.

It’s already 10’clock. I wonder how it ____ that she was two hours late on such a short trip.

The leaders from six countries are discussing whether it is necessary to ____a special committee to deal with the worldwide terror attack. [ ]