adj 用來控制文字的對齊方式，取值範圍為0到1，控制圖片中x軸和y軸標簽，標題，以及通過text 添加的文字的對齊方式

0表示左對齊，代碼示例：

par(adj = 0)
plot(1:5, 1:5, type = "n", main = "title", xlab = "x", ylab = "y")
abline(h = 3, lty = 2)
abline(v = 3, lty = 2)
text(x = 3, y= 3, label = "text", cex = 2)

效果圖如下：

0.5為默認值，表示居中對齊，代碼示例：

par(adj = 0.5)
plot(1:5, 1:5, type = "n", main = "title", xlab = "x", ylab = "y")
abline(h = 3, lty = 2)
abline(v = 3, lty = 2)
text(x = 3, y= 3, label = "text", cex = 2)

效果圖如下：

1代表右對齊，代碼示例：

par(adj = 1)
plot(1:5, 1:5, type = "n", main = "title", xlab = "x", ylab = "y")
abline(h = 3, lty = 2)
abline(v = 3, lty = 2)
text(x = 3, y= 3, label = "text", cex = 2)

效果圖如下:

par函數的adj 參數- 控制文字的對齊方式