Steve Jobs’ success in digital field proved ______ it took to be a best CEO.
| A．what | B．which | C．that | D．how |
I really don’t know _________ I put my wallet after I paid the bill．
| A．where was it | B．it was where that |
| C．where was it that | D．where it was that |
During the examination we are required to stay in our seats, keep our eyes on our work, ____ to anyone.
| A．instead of speaking | B．rather than speak |
| C．and not to speak | D．but would not speak |
________ these experiments were successfully completed would we think of going into humans.
| A．If only | B．Only if | C．So that | D．Even if |
Currently, many American women are still faced with the ________ of choosing between work and family commitments.
| A．desperation | B．dilemma | C．confusion | D．Concern |
Tony ________ full marks, but he was so careless as to make a spelling mistake.
| A．could have gained | B．can have gained |
| C．must have gained | D．must gain |