For more than a decade, experts from across the globe ________ on the cure of the disease that way.
| A．worked | B．are working | C．have been working | D．were working |
Many a student ____ going to have themselves ______ in the hospital.
| A．is ; to examine | B．are ; examine | C．is ; examined | D．are ; examining |
The ship would have sunk with all on board ______ for the captain.
| A．if it was not | B．had it not been | C．if it has not been | D．not had it been. |
Sitting at the back of the room but in front of some old men and women ______ a very shy girl with two bright eyes.
| A．was | B．were | C．are | D．being |
They wouldn’t agree to sell the house to us at the same price ______ they had promised, ______ was rather disappointing.
| A．which ; as | B．as ; that | C．as ; which | D．that ; that |
Life is like time; once , it never returns.
| A．to lose | B．losing | C．lost | D．being lost |