阿摩線上測驗
49.In the passage, the phrase “waning immunity” most likely means:
(A) An increase in immune system strength over time
(B) The gradual loss of protection against infection
(C) A sudden and permanent breakdown of the immune system
(D) The immediate failure of a vaccine to provide any protection
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統計： A(1), B(17), C(1), D(0), E(0) #3427207
統計： A(1), B(17), C(1), D(0), E(0) #3427207
