开方: [数学] extracting; extract a root; extraction of a root; evolution 短语和例子开立方 extract the cube root; 开平方 extract the square root; radication; extract a root
大开方便之门: open the floodgates wide to [for] (sb.); do everything to suit sb.'s convenience; facilitate sth.; give facility to sb.; give the green light to; make it convenient for (sb. to do sth.); p