The price system is a complex network composed of the prices of all the products bought and sold in the economy as well as of a great number of services.
| A．the one | B．that | C．ones | D．those |
When lastvaluable, those books enjoyed great success.
| A．finding | B．found | C．being found | D．to be found |
He knows little of mathematics, of chemistry.
| A．and still less | B．as well as | C．and still more | D．no less than |
Discovering consists of seeing what everybody has seen andwhat nobody has thought.
| A．think | B．thinking | C．thought | D．to think |
—Did the policeman let you in?—No, I told him who I was.
| A．if | B．once | C．as though | D．even though |
He likesmusic so much that I think it right to buy himMP3 asbirthday present.
| A．the; an; a | B．不填；an; the | C．不填；an；a | D．the；a; a |