I ____ at my new novel when the big earthquake happened at 2:20 pm.
| A．am working | B．was working | C．have worked | D．had been working |
Distinguished guests and friends, welcome to our school, the ceremony of the 50th Anniversary this morning are our alumni （校友） from home and abroad.
| A．Attend | B．To attend | C．Attending | D．Having attended |
Schools across China are expected to hire 50,000 college graduates this year as short-term teachers, almost three times the number hired last year, reduce unemployment pressures.
| A．help | B．to have helped | C．to help | D．having helped |
When hethe door, he found his keys were nowhere.
| A．would open | B．opened | C．had opened | D．was to open |
In April, 2009, President Hu inspected the warships in Qingdao, the 60th anniversary of the founding of the PLA Navy.
| A．marking | B．marked | C．having marked | D．being marked |
not to miss the flight at 15:20, the manager set out for the airport in a hurry.
| A．Reminding | B．Reminded | C．To remind | D．Having reminded |