scala:如何使超类的变量隐含在子类的作用域中

class SuperClass {
  val superVariable: String = "Super Variable"
}

class SubClass extends SuperClass {
  val subVariable: String = "Sub Variable"

  def printVariables(): Unit = {
    println(superVariable) // 可以直接访问超类的变量
    println(subVariable)
  }
}

val obj = new SubClass()
obj.printVariables()

Super Variable
Sub Variable