设某发动机的进气提前角为α，进气迟关角为β，排气提前角为γ，排气迟关角为δ，则该发动机的进、排气门重叠角为

设某发动机的进气提前角为α，进气迟关角为β，排气提前角为γ，排气迟关角为δ，则该发动机的进、排气门重叠角为
A.α+δ
B.β+γ
C.α+γ
D.β+δ
正确答案：α+δ