People have always been curious how living things on the earth exactly began.
| A．in | B．at | C．of | D．about |
We must show concern ___ each other.
| A．to | B．for | C．with | D．at |
---Peter, you set down the result of the experiment, ___________?
---Oh, yes, but I need to find my pen first.
| A．will you | B．shall you | C．don’t you | D．do you |
Rio De Janeiro, ___________the right to host the 2016 Olympic Games, will be occupied in building stadiums.
| A．winning | B．won | C．having won | D．to win |
There is growing tendency among middle-school students___________they will do some voluntary work during their vacation.
| A．which | B．why | C．how | D．that |
---Will you set out to carry out the project?
---Yes. We have already___________ most carefully the time and money needed to complete it.
| A．picked out | B．left out | C．taken out | D．figured out |