facet_grid:修改每个facet的x轴标签

Question

我无法修改第二个面上的x轴标签。第一个方面的内容很好，但是如何创建第二个方面的内容-- 119、121、130、133

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下面是我的代码：

data$treatment <- factor(data$treatment, levels = c("baseline", "3m"))
labels<- c(`baseline` = "Baseline",`3m` = "3 m after") 

p <- ggplot(data = data, aes(x = day, y = BL.P, group = mechanism)) +
geom_line(aes(color = mechanism), size = 1) +
geom_point(aes(color = mechanism), size = 3) +
scale_color_manual(values = c("#CC79A7", "#0072B2", "#000000"), 
                   name = "Mechanism") + 
labs(title = "Title", x = "Day", y = "Proportion (%)") +


p + facet_grid(~treatment, scales = "free_x", space = "free_x", 
               labeller = labeller(treatment = labels)) +  
    scale_x_continuous(breaks = seq(1,21,by = 1), 
                       labels = c("1","3","5","8","10","15","17","19","22","24",
                                  "26","29","31","33","36","38","40","43","45",
                                  "47","50")) +
    theme(strip.text.x = element_text(size = 12, face = "bold"))    

这是我的数据：https://www.dropbox.com/s/kppvgucdwa20otd/data.csv?dl=0

我是一个完全的R初学者，这是我的第一个数字之一。如果可能的话，我会非常感谢一个简单的解决方案...