单项选择题
A.400 B.500 C.600
A.一次缓解 B.二次缓解 C.阶段缓解
A.5~7S B.7~9S C.10~15S D.25~28S
A.0.65~0.8 B.0.7~0.9 C.0.5~0.6 D.0.9~1
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