A、<span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-bidi-font-family: " times="" new="" roman";="" mso-ascii-theme-font:="" minor-fareast;="" mso-fareast-theme-font:="" mso-hansi-theme-font:="" mso-font-kerning:="" 1.0pt;="" mso-ansi-language:="" en-us;="" mso-fareast-language:="" zh-cn;="" mso-bidi-language:="" ar-sa"="">永久作用</span>
B、<span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-bidi-font-family: " times="" new="" roman";="" mso-ascii-theme-font:="" minor-fareast;="" mso-fareast-theme-font:="" mso-hansi-theme-font:="" mso-font-kerning:="" 1.0pt;="" mso-ansi-language:="" en-us;="" mso-fareast-language:="" zh-cn;="" mso-bidi-language:="" ar-sa"="">可变作用</span>
C、<span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-bidi-font-family: " times="" new="" roman";="" mso-ascii-theme-font:="" minor-fareast;="" mso-fareast-theme-font:="" mso-hansi-theme-font:="" mso-font-kerning:="" 1.0pt;="" mso-ansi-language:="" en-us;="" mso-fareast-language:="" zh-cn;="" mso-bidi-language:="" ar-sa"="">其它可变作用</span>
D、偶然作用