图示简支梁中间截面的弯矩为( )
····<img src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/examination/imgUplod/1701141266176402d9ac99b5542098903f2eef143eb78image5.png" 2.
出自:川北医学院口腔医学院