• 2022-06-01
    ‎以下约束方程中,属于非定常约束的有( )。‎
    A: [img=107x36]180341f7a53a947.png[/img]
    B: [img=107x53]180341f7ae2d0d7.png[/img]
    C: [img=107x32]180341f7b6f8fdd.png[/img]
    D: [img=107x33]180341f7c02e801.png[/img]