Gradle下载不了，可以使用阿里的依赖库

将项目路径下的build.gradle

buildscript {
    
    repositories {
        google()
        jcenter()
        
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.6.1'

    }
}

allprojects {
    repositories {
        google()
        jcenter()
        
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

修改为

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    
    repositories {
        // 添加阿里云 maven 地址
        maven { url 'http://maven.aliyun.com/nexus/content/groups/public/' }
        maven { url 'http://maven.aliyun.com/nexus/content/repositories/jcenter' }
        google()
        jcenter()
        
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.6.1'
        

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        // 添加阿里云 maven 地址
        maven { url 'http://maven.aliyun.com/nexus/content/groups/public/' }
        maven { url 'http://maven.aliyun.com/nexus/content/repositories/jcenter' }
        google()
        jcenter()
        
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

或者是在Android Studio的Settings中添加如下设置，下次就不用再改动这个文件了