It is known to all that ____ you exercise regularly, you won’t stay healthy.
| A．because | B．unless | C．now that | D．in case |
—You were brave enough to raise objection at the meeting.
—Well, now I regret _______ that.
| A．to do | B．to be doing | C．to have done | D．having done |
The first textbooks _______ for teaching English as a foreign language came out in the 16th century.
| A．having written | B．to be written | C．being written | D．written |
Apartments in cities can be quite high. Renters are paying up to $1,000 per month for _______ bedroom apartment.
| A．one a | B．the one | C．one | D．a one |
As is known to us all, _____ tiger is in _____ danger of becoming extinct.
| A．the, a | B．the, 不填 | C．a, 不填 | D．不填, the |
This is _____ best kind of _____ pen you can get here.
| A．the, the | B．the, a | C．the, 不填 | D．a, the |