How to plot two lines, and only one line with errorbar by qqplots of R

Here is my code, which plots three lines with errorbar. How could I add an
extra line without errorbar to the plot? Thank you very much.


beta.data <- data.frame (
method = rep(c("Wrong", "Correct", "Full Bayes"), each = T_obs),
mean.beta = c(mean.beta1, mean.beta2, mean.beta3),
t = rep(points, 3),
std.beta = c(std.beta1, std.beta2, std.beta3)
)


limits = aes(ymin = mean.beta - std.beta, ymax = mean.beta + std.beta);
maintitle = paste("beta function (std = ", std, ")", sep = "");


p + geom_line() + geom_errorbar(limits, width = 0.05) + ggtitle(maintitle) +
  theme(legend.title=element_blank(), legend.justification=c(0,1),
  legend.position=c(0,1))+
  scale_x_continuous(breaks=seq(0, 10, .1)) +
  scale_y_continuous(breaks=seq(0, 13, .1)) +
  ylab("Beta(t)") + scale_colour_hue(breaks=c("Wrong", "Correct", "Full Bayes"))