for循环里我加了打印序号，结果显示通道关闭以后，for循环也结束了。老师，这是什么原因啊？

package main

import "fmt"

func main() {
    ch4 := make(chan int, 1)
    for i := 0; i < 4; i++ {
        fmt.Printf("序号：%d\n", i)
        select {
        case e, ok := <-ch4:
            if !ok {
                fmt.Println("End.")
                return
            }
            fmt.Println(e)
            close(ch4)
        default:
            fmt.Println("No Data!")
            ch4 <- 1
        }
    }
}