He stumbled(绊倒)on the _______ ground and fell flat on his face.
| A．undeniable | B．unfair | C．unavoidable | D．uneven |
The incomes of skilled workers went up. ____, unskilled workers saw their earnings fall.
| A．Meanwhile | B．Moreover | C．Therefore | D．Otherwise |
–Mom, I will send you a gift for your birthday, ____ beyond your imagination.
--Oh, dear, thanks.
| A．which | B．what | C．the one | D．something |
____ the machine, the engineers paid much attention to the noise from it.
| A．Having examined | B．Being examined | C．Examining | D．Examined |
____ the 1990s, the number of antelopes had fallen to about 50,000.
| A．During | B．Since | C．By | D．Over |
If the machine makes a mistake -- ____ rarely happens -- it gives a warning in the form of a red light.
| A．that | B．which | C．as | D．what |