____ he referred to in his article was unknown to the general reader.
| A．That | B．What | C．Whether | D．Where |
—You seem to have lost your way. ______?
—I’m looking for the nearest post office.
| A．What for | B．Need help | C．Where to | D．What if |
—You should have given me a ring before you left.
—I meant______, but I was in a hurry that time.
| A．to do | B．to | C．do | D．doing it |
Some researchers believe that there is no doubt ______a cure for AIDS will be found.
| A．which | B．whether | C．that | D．what |
He was about to tell me the secret ______ someone patted him on the shoulder.
| A．as | B．while | C．when | D．until |
______ you’re tried it, you can’t imagine how pleasant it is.
| A．When | B．Although | C．Because | D．Unless |