package main

import (
    "fmt"
)

func main() {
    var x string
    x = "Hello"

    y := "world"

    var sentence string = x + ", " + y + "!"

    fmt.Println(sentence)
    fmt.Printf("%s, %s!", y, x)
}

As you can see, Go is a kind of combination of Python, C++, JavaScript.

1. package, have no idea yet.

2. func main() {} is like C or C++ codes structure, which without ; to determine if a statement was finished.

3. var x string is like the way of declaring a variable in JavaScript.

4. y := "world" is like Python, in there, the compiler will automatically figure out the variable type without you to declare.
   fmt.Println() is like Python's print(), and revealed the relationship of Class and Function.