In developed countries, before toxic chemicals are released into rivers and lakes; they should be treated in order to avoid ______.

A．Talk to his sister.
B．Look at a map.
C．Go on a diet.
D．Tell the man why.

A．She was impressed by it.
B．It was a waste of money.
C．She was amazed it had opened so soon.
D．She didn’t like it as much as the other wings.