我安装了 sbt-1.3.4.msi 当试图建立一个样本时 SparkPi.scala 应用程序，我得到以下错误：

C:\myapps\sbt\sparksample>sbt
[info] Loading project definition from C:\myapps\sbt\sparksample\project
[info] Compiling 1 Scala source to C:\myapps\sbt\sparksample\project\target\scala-2.12\sbt-1.0\classes ...
[error] C:\myapps\sbt\sparksample\project\src\main\scala\SparkPi.scala:3:19: object spark is not a member of package org.apache
[error] import org.apache.spark._
[error]                   ^
[error] C:\myapps\sbt\sparksample\project\src\main\scala\SparkPi.scala:8:20: not found: type SparkConf
[error]     val conf = new SparkConf().setAppName("Spark Pi")
[error]                    ^
[error] C:\myapps\sbt\sparksample\project\src\main\scala\SparkPi.scala:9:21: not found: type SparkContext
[error]     val spark = new SparkContext(conf)
[error]                     ^
[error] three errors found
[error] (Compile / compileIncremental) Compilation failed

这个 SparkPi.scala 文件位于 C:\myapps\sbt\sparksample\project\src\main\scala （如上面的错误消息所示）。
我错过了什么？
这个 C:\myapps\sbt\sparksample\sparksample.sbt 文件如下：

name := "Spark Sample"

version := "1.0"

scalaVersion := "2.12.10"

libraryDependencies += "org.apache.spark" %% "spark-core" % "3.0.0"