inverted plumb line线: thread; string; wire观测大坝挠度用倒垂线: reversedpendulum垂线: (与另一条直线或平面相垂直的直线) perpendicular; vertical; [数学] vertical line; perpendicular line倒垂的: inverted倒垂帘: closing down the shade下载手机词典可随时随地查词查翻译
