18. As more and more species are faced with extinction, how to sustain biodiversity is great significance to human beings.
(A)under
(B)of
(C)about
(D)beyond
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統計: A(52), B(204), C(108), D(68), E(0) #1918578
統計: A(52), B(204), C(108), D(68), E(0) #1918578
