阅读下面的短文，文中有15处空白，每处空白给出4个选项。请根据短文的内容，从4个选项中选择1个最佳答案。Reading Reading involves looking at graphic symbols and formulating mentally the sounds and ideas they represent. Concepts of reading have changed substantially over the centuries. During the 1950’s, and 1960’s especially, increased attention has been devote (51) defining and describing the reading process. (52) specialists agree that reading (53) a complex organization of higher mental (54) , they disagree (55) the exact nature of the process. Some experts, who regard language primarily as a code using symbols to represent sounds, (56) reading as simply the decoding of symbols into the sounds they stand (57) . These authorities (58) that meaning, being concerned with thinking, must be taught independently of the decoding process. Others maintain that reading is inextricably related to thinking, and that a child who pronounces sounds without (59) their meaning is not truly reading. The reader, (60) some, is not just a person with a theoretical ability to read but one who (61) reads. Many adults, although they have the ability to read have never read a book in its entirety. By some experts they would not be (62) as readers. Clearly, the philosophy, objectives, methods and materials of reading will depend on the definition one uses. By the most inclusive and satisfactory definition, reading is the ability to (63) the sound-symbol code of the language, to interpret meaning for various purposes, at various rates, and at various levels of difficulty, and to do (64) widely and enthusiastically. (65) , reading is the interpretation of ideas through the use of symbols representing sounds and ideas.

A. breaks up
B. elaborate
C. define
D. unlock