______ life began on earth is one of the biggest puzzles that scientist found hard ______.
| A．How; solving | B．When; to be solved |
| C．How; to solve | D．Which; to solve |
— Are you in favour of Tom’s suggestion_______ we work around the clock to meet the deadline?
— No. But ______ Jimmy suggested to me sounds practical.
| A．which; what | B．that; that |
| C．which; that | D．that; what |
We attend lectures in the school meeting room at weekend _______ seats more than 800 students.
| A．which | B．whose |
| C．where | D．it |
How can you expect to get ahead in your life _______you even live to yourself from time to time?
| A．though | B．until |
| C．before | D．when |
Much disappointed as he is _______ in the job interview, he still keeps his confidence.
| A．to have failed | B．failed |
| C．having failed | D．failing |
Time is pressing; it’s impossible for me to get there in an hour, ______ the possible delays.
| A．accounting for | B．answering for |
| C．allowing for | D．heading for |