If you want to study history, you should call ________.

A．Dictionaries have little effect on learning to speak English.
B．No matter what new words you meet while reading, never use dictionaries.
C．Small two-language dictionaries have serious defects(缺陷).
D．Reading something for the first time, you' d better not use dictionaries.

A．that students shouldn't use small two-language dictionaries
B．when were the defects of small two-language dictionaries
C．why students should use large college edition dictionaries
D．what dictionary students should choose and how to use it