A、<span style="FONT-FAMILY: 宋体; mso-ascii-font-family: \'Times New Roman\'; mso-hansi-font-family: \'Times New Roman\'; mso-font-kerning: 1.0pt; mso-bidi-font-family: \'Times New Roman\'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">当且仅当<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/fb514686-f24b-4789-a45b-d208dda37bc8.gif"title="ex_1303439596387_0.gif" alt="ex_1303439596387_0.gif"/><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: \'Times New Roman\'; mso-hansi-font-family: \'Times New Roman\'; mso-font-kerning: 1.0pt; mso-bidi-font-family: \'Times New Roman\'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">时引起的与<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/00ec0ca1-05dd-4f01-aff2-b51b0882420c.gif"title="ex_1303438339829_0.gif" alt="ex_1303438339829_0.gif"/><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: \'Times New Roman\'; mso-hansi-font-family: \'Times New Roman\'; mso-font-kerning: 1.0pt; mso-bidi-font-family: \'Times New Roman\'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">相应的杆端力；</span></span></span>
B、<span style="FONT-FAMILY: 宋体; mso-ascii-font-family: ">当且仅当<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/eb55cdef-debf-4e91-88e0-eb91d0054940.gif"title="ex_1303439697110_0.gif" alt="ex_1303439697110_0.gif"/><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: ">时引起的与<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/bcfbbfcd-f5a8-478f-ba35-3993248efa04.gif"title="ex_1303438447289_0.gif" alt="ex_1303438447289_0.gif"/><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: \'Times New Roman\'; mso-hansi-font-family: \'Times New Roman\'; mso-font-kerning: 1.0pt; mso-bidi-font-family: \'Times New Roman\'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">相应的杆端力；</span></span></span>
C、<span style="FONT-FAMILY: 宋体; mso-ascii-font-family: ">当<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/640a5102-3fd2-4969-ae15-45b64f99e4ba.gif"title="ex_1303439816852_0.gif" alt="ex_1303439816852_0.gif"/><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: ">时引起的与<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/93ff5a74-460f-49b5-9609-dac62959f3d8.gif"title="ex_1303439874000_0.gif" alt="ex_1303439874000_0.gif"/><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: ">相应的杆端力；</span></span></span>
D、<span style="FONT-FAMILY: 宋体; mso-ascii-font-family: ">当<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/6d070ac9-39f8-485b-a398-d11c5d546929.gif"title="ex_1303438618625_0.gif" alt="ex_1303438618625_0.gif"/><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: ">时引起的与<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/b76d0ed7-bcb9-4a0f-aa41-927787bd7d53.gif"title="ex_1303439974519_0.gif" alt="ex_1303439974519_0.gif"/><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: ">相应的杆端力。</span></span></span>
A、<span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">当且仅当<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/fb514686-f24b-4789-a45b-d208dda37bc8.gif"title="ex_1303439596387_0.gif" alt="ex_1303439596387_0.gif"/><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">时引起的与<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/00ec0ca1-05dd-4f01-aff2-b51b0882420c.gif"title="ex_1303438339829_0.gif" alt="ex_1303438339829_0.gif"/><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">相应的杆端力；</span></span></span>
B、<span style="FONT-FAMILY: 宋体; mso-ascii-font-family: ">当且仅当<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/eb55cdef-debf-4e91-88e0-eb91d0054940.gif"title="ex_1303439697110_0.gif" alt="ex_1303439697110_0.gif"/><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: ">时引起的与<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/bcfbbfcd-f5a8-478f-ba35-3993248efa04.gif"title="ex_1303438447289_0.gif" alt="ex_1303438447289_0.gif"/><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">相应的杆端力；</span></span></span>