closed onv.靠近(接近；差不多)closedadj.关闭的；封闭的；停业的动词close的过去式和过去分词.closed-loop gain闭环增益closed pore volume闭孔体积closed end spanner闭口扳手closed-loop zero闭环零点Closed oil circuit闭式油路closed their doorsv.拒而不纳(关门停业)closed cooling box密闭式冷却箱closed vortex line封闭涡线closed under union[计] 对"或"运算封闭closed coil spring关闭式螺旋弹簧