A) although C) when
B) because D) if

A．This method needs improving in spite of its obvious advantages.
B．This method is most effective when used unconsciously.
C．This method, if used properly, will improve one's comprehension.
D．This method is particularly useful for foreign language learners.

A．have some knowledge of the overall structure and details of a text
B．take a piece of card and mask the text and reveal one section at a time
C．memorize all the details of the text
D．keep in mind the author's purpose in writing the article