如何才能使大量的ggplot图形在R中的两列中打印，而不将它们展平？

library(ggplot2)
library(gridExtra)

# 创建多个ggplot图形
plot1 <- ggplot(mtcars, aes(x = mpg, y = disp)) + geom_point()
plot2 <- ggplot(mtcars, aes(x = mpg, y = hp)) + geom_point()
plot3 <- ggplot(mtcars, aes(x = mpg, y = wt)) + geom_point()
plot4 <- ggplot(mtcars, aes(x = mpg, y = qsec)) + geom_point()

# 将图形按照2列布局排列在一起
grid.arrange(plot1, plot2, plot3, plot4, ncol = 2)

library(ggplot2)
library(cowplot)

# 创建多个ggplot图形
plot1 <- ggplot(mtcars, aes(x = mpg, y = disp)) + geom_point()
plot2 <- ggplot(mtcars, aes(x = mpg, y = hp)) + geom_point()
plot3 <- ggplot(mtcars, aes(x = mpg, y = wt)) + geom_point()
plot4 <- ggplot(mtcars, aes(x = mpg, y = qsec)) + geom_point()

# 将图形组合在一起，并在两列中打印它们
plot_grid(plot1, plot2, plot3, plot4, ncol = 2)