r在四个情节的底部放置一个图例

目前我有以下4个图：

qqnorm(Adrt,
   main="QQplot for Admiral (Normal)",
   cex.main=2,
   cex.lab=1.5)
qqline(Adrt, col="blue", lwd=1)

qqplot(as.numeric(Adrt), rstd(260, mean = Adrt_Tmu, sd = Adrt_Tsd, nu = Adrt_Tnu),
   main="QQplot for Admiral (Student-t)",
   xlab = "Theoretical Quantiles",
   ylab = "Sample Quantiles",
   cex.main=2,
   cex.lab=1.5)
qqline(as.numeric(Adrt),
   distribution = function(p) qstd(p, mean = Adrt_Tmu, sd = Adrt_Tsd, nu = Adrt_Tnu),
   col="red", lwd=1)

qqplot(as.numeric(Adrt), rsstd(260, mean = Adrt_skewTmu, sd = Adrt_skewTsd, nu = Adrt_skewTnu, xi = Adrt_skewTxi),
   main="QQplot for Admiral (Skewed-t)",
   xlab = "Theoretical Quantiles",
   ylab = "Sample Quantiles",
   cex.main=2,
   cex.lab=1.5)
qqline(as.numeric(Adrt),
   distribution = function(p) qsstd(p, mean = Adrt_skewTmu, sd = Adrt_skewTsd, nu = Adrt_skewTnu, xi = Adrt_skewTxi),
   col="green", lwd=1)

qqplot(as.numeric(Adrt), rsnorm(260, mean = Adrt_skewNmu, sd = Adrt_skewNsd, xi = Adrt_skewNxi),
   main="QQplot for Admiral (Skewed-Normal)",
   xlab = "Theoretical Quantiles",
   ylab = "Sample Quantiles",
   cex.main=2,
   cex.lab=1.5)
qqline(as.numeric(Adrt),
   distribution = function(p) qsnorm(p, mean = Adrt_skewNmu, sd = Adrt_skewNsd, xi = Adrt_skewNxi),
   col="orange", lwd=1)

我想把QQline的图例放在图表的底部，这样它就不在它们里面了。 我还需要他们被分散在整个底部。因此，不是4行1列1行4列

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谢谢

我曾经尝试过使用布局功能，但对它几乎没有经验。非常感谢您的帮助！提前谢谢。我试过使用布局功能，但经验很少。非常感谢您的帮助！提前谢谢。