The book has helped me greatly in my daily communication, especially at work ________ a good impression is a must.
| A．which | B．when |
| C．as | D．where |
I have two elder brothers, ____ in the army for ten years.
| A．the elder of whom served |
| B．the older having served |
| C．the older of which served |
| D．the elder one has served |
Nothing could be done at the meeting, the chairman_____ absent.
| A．being | B．was |
| C．to be | D．be |
Bats are surprisingly long-lived creatures, some ____________ a life span of around 20 years.
| A．having | B．had |
| C．have | D．to have |
UN Secretary-General Ban Ki-moon left for Pakistan this morning， his assistant _________ him there this Friday.
| A．joins | B．joined |
| C．joining | D．to join |
______, the conference began.
| A．The candidates having taken their seats |
| B．The candidates had taken their seats |
| C．Taken their seats |
| D．Taking their seats |