Classified by different aims, there are at least 4 major types of test, among which ______ is to discover what the testee already knows about the target language.

A．all of the effects of pollution on the human body
B．how pollution can be controlled successfully
C．when the atmosphere first became polluted
D．how to wash the black snow clean

A．To save money on food.
B．To buy food without additives.
C．To do all his shopping in one place.
D．To meet other health - conscious peopl