[ Swift ] synthesizer.speak 怎么出声？

#!/usr/bin/env swift import AVFoundation // Create an utterance. let utterance = AVSpeechUtterance(string: "The quick brown fox jumped over the lazy dog.") // Configure the utterance. utterance.rate = 0.57 utterance.pitchMultiplier = 0.8 utterance.postUtteranceDelay = 0.2 utterance.volume = 0.8 // Retrieve the British English voice. let voice = AVSpeechSynthesisVoice(language: "en-GB") // Assign the voice to the utterance. utterance.voice = voice // Create a speech synthesizer. let synthesizer = AVSpeechSynthesizer() // Tell the synthesizer to speak the utterance. synthesizer.speak(utterance) synthesizer.speak(AVSpeechUtterance(string: "Hello The quick brown fox jumped over the lazy dog.")) var myString = "Hello, World!" print(myString) 

为啥这个没有声音，synthesizer 不能用 swsh 脚本使用？ 我是纯小白，也没学过 swift 今天发现 mac 的朗读功能挺有意思的就想调一下这个接口玩玩，但是发现没动静 感觉我的语法没问题啊，应该是 使用姿势不对吧，求指点要怎么用

目前就是想这个 出声音，求解