Samuel Clemens, _______ as Mark Twain, was one of the most famous American writer.
| A．to know | B．to be known | C．known | D．knowing |
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 |
He never complains about the difficulties he has in life．_______，he always has ways to overcome them．
| A．However | B．Otherwise | C．Instead | D．Therefore |