Some passers-by witnessed the car accident ______ five passengers were killed, a baby included.
| A．where | B．which |
| C．that | D．when |
—Do you know ____ made him successful in his career?
—Yes. His hard work and determination, of course.
| A．what it was that |
| B．what was it that |
| C．it was what that |
| D．was it what that |
With many cities in China dreadfully blanketed by thick haze, the environment problem is _____ Chinese people concern most nowadays.
| A．what | B．which |
| C．where | D．when |
—It is a mystery and a shock to all who knew him that he____ have taken his own life in this way.
—What a pity, indeed.
| A．must | B．may |
| C．can | D．should |
_____, everyone present was amused by his adventure story in Africa.
| A．Absurd as might it sound |
| B．As it might sound absurd |
| C．As absurd it might sound |
| D．Absurd as it might sound |
_____ he is enthusiastic and qualified for the job, I see no reason to remove him from office.
| A．Provided that | B．Even though |
| C．Unless | D．As if |