All the photographs in this book, _______ stated otherwise, date from the 1970s.
| A．until | B．once | C．if | D．unless |
I have been living in the United States for twenty years, but seldom_______ so lonely as now.
| A．have I felt | B．I had felt | C．I have felt | D．had I felt |
Today’s teens don’t see anything strange in the fact _______the computer takes up a central place in their social lives.
| A．which | B．that | C．where | D．what |
I _______to go shopping that Saturday, but the bad weather made me change my mind.
| A．plan | B．would plan | C．had planned | D．have planned |
---______ the farmers discovered the entrance to the secret cave in the valley?
--- Totally by chance.
| A．When was it that | B．How was it that | C．How it was that | D．When it was that |
One more month, _______ the grapes in the yard will be ripe.
| A．or | B．otherwise | C．but | D．and |