10. The junk floating in outer space poses a great danger to both astronauts and their spacecraft.
(A) potential
(B) process
(C) probability
(D) problem
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統計: A(43), B(34), C(37), D(142), E(0) #3060392
統計: A(43), B(34), C(37), D(142), E(0) #3060392