Noun1.equivalent word- two words that can be interchanged in a context are said to be synonymous relative to that context synonym word- a unit of language that native speakers can identify; "words are the blocks from which sentences are made"; "he hardly said ten words all morning" ...
A. Because they are closely related to Africa's problem. B. Because they make up a great proportion of human society. C. Because they are the essential reason for environmental problems. D. Because they can provide financial support for environmental protection. 69. What is the most importa...