Sometimes_________good knowledge of_________ first aid may mean the difference between life and death.
| A．a; / | B．/; the | C．/; / | D．a; the |
We haven't settled the question of ______ it is necessary for him to study abroad.
| A．if | B．where | C．whether | D．that |
A poet and artist ______ coming to speak to us about Chinese literature and painting tomorrow afternoon.
| A．is | B．are | C．was | D．were |
I wish you'd do ______ talking and some more work. Thus things will become better.
| A．a bit less | B．any less | C．much more | D．a little more |
—There is a story here in the paper about a 110-year-old man.
—My goodness! I can't imagine______ that old.
| A．to be | B．to have been | C．being | D．having been |
______ environmental damage is done, it takes many years for the ecosystem to recover.
| A．Even if | B．If only | C．While | D．Once |