—I wonder how much you charge for your services.
—The first two are free ________ the third costs $30.
| A．while | B．until | C．when | D．before |
I would appreciate ______, to be frank, if goods could be delivered as soon as possible.
| A．you | B．this | C．it | D．myself |
I’ll be publishing my results only when I have _________ my research.
| A．concerned | B．connected | C．conducted | D．concluded |
—What do you think of Spain?
—Well, considering its diverse cultures, it is an attractive country,______ worthy of a visit.
| A．it | B．one | C．this | D．that |
____ enters the computer rooms should take off his shoes in order to keep them clean enough.
| A．Who | B．Whoever | C．What | D．Whatever |
I just wonder ______ that makes him so excited.
| A．why it does | B．what he does | C．how it is | D．what it is |