Innovation is a natural desire of the human mind to develop variety，__________ activity is involved.
| A．no matter when |
| B．however |
| C．whatever |
| D．no matter which |
We were delayed at the train station．Otherwise，we here by lunch．
| A．must have been | B．could be |
| C．should be | D．would have been |
The teaching building, to be environmentally friendly, will be completed next year.
| A．designed | B．designing |
| C．being designed | D．having designed |
The president stressed that young people's values determine the values of the future society, and more efforts should be made to ensure young people's cultivation of sound value systems, ________ are still in the formation stage.
| A．which | B．what | C．when | D．where |
—The tickets for the concert have been sold out.
—Thanks for reminding me, but I am lucky to have got .
| A．another | B．it | C．that | D．one |
—How is your mother?
—She_________ quite good after the operation, but she is taking a turn for the worse today.
| A．felt | B．feels | C．had felt | D．has been feeling |