________ that the Youth Olympic Games might be delayed due to severe air pollution, our government has made a promise to Jacques Rogge that they will spare no effort to settle the problem.
A．Warned B．Having warned
C．Warning D．Being warned
During the flood many students volunteered ________ through the weekend, giving out food and water for the victims.
A．working B．to work
C．to have worked D．having worked
Our waste recycling project ________ a lot of investigation and paperwork had been done by the end of last term.
A．involved B．to involve
C．being involved D．involving
Every morning Jack's wife will stand before the mirror, ________ carefully until she has to go to work.
A．dressed B．dressing
C．to dress D．having dressed
________ for a whole night, we still couldn't agree on when to start and where to go for the holiday.
A．Discussed B．Having discussed
C．Discussing D．Being discussed
In my opinion, keeping dogs well ________ up is advisable for dog owners.
A．to tie B．being tied
C．tied D．to be tied
