Many early Europeans, ________ the earth to be flat, feared that Columbus would fall off the edge of the earth.
| A．believing | B．having believed | C．believed | D．to believe |
It was 80 years before Christopher Columbus crossed the AtlanticZheng He sailed to East Africa
| A．when | B．that | C．after | D．since |
Before you quit your job, how your family would feel about your decision.
| A．consider | B．considering | C．to consider | D．considered |
All the photographs in this book,stated otherwise, date from the 1950s.
| A． | unless | B． | until | C． | once | D． | if |
—Can I call you back at two o’clock this afternoon?
—I’m sorry, but by then I______ to Beijing. How about five?
| A．fly | B．will fly | C．will be flying | D．am flying |
I______ thank you too much for all your help to my son while we were away from home.
| A．won’t | B．can’t | C．can | D．will |