x <- 1:2
y <- runif(2,0,100)
par(mar=c(4,6,2,6))
plot(x,y,type="n",xlim=c(0.5,2.5),ylim=c(-10,110),axes=F,ann=F) axis(2,at = seq(0,100,20))
mtext("Temp (Centigrade)",side=2,line=3) axis(1,at=1:2,labels = c("T1","T2"))
axis(4,at=seq(0,100,20),labels = seq(0,100,20)*9/5 + 32)
mtext("Tepm (Fahrenheit)",side=4,line=3)
box() segments(x,0,x,100,lwd=20)
segments(x,0,x,100,lwd=16,col="white")
segments(x,0,x,y,lwd=16,col="gray")
参考：
R Graphics (2nd Edition)