围绕本课标题 Knock, knock! 咚咚敲门声（咚咚敲门声 · 花园里的午餐）主题，AI 老师会出 若干个简单问题，
每个问题听完后，用 完整句子口头作答。
⚠️ 尽量说完整句子，不要只说一个词；优先用本课句型与词语：Isn't there anyone at home / Everything's very quiet / that's impossible / Can you see anything / Nothing at all / Everyone's in the garden / She's only joking