折: 折动词[口语]1.(翻转) roll over; turn over 短语和例子折跟头 turn somersault; 折过儿 turn over; 折来折去 roll about2.(倒过来倒过去) pour back and forth between two containers 短语和例子开水太烫, 拿两个杯子折一折就凉了。 the water's boiling
垂直: perpendicular; vertical; squareness; verticality; perpendicularity 短语和例子两线垂直相交。the two lines meet at right angles. 设 ab 垂直于 cd。let ab be perpendicular to cd. 当表面与射线垂直时，射线的强度最大。when a surfa
