围绕本课标题 Not a gold mine 并非金矿（探宝落空）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：Dreams of finding lost treasure almost came true / A new machine called the Revealer / has been invented / has been used to detect gold / buried in the ground / in a cave near the seashore / pirates used to hide gold / Armed with the new machine / a search party went into the cave / the soil near the entrance to the cave / dug a hole two feet deep / a small gold coin which was almost worthless / searched the whole cave thoroughly / an empty tin trunk / In spite of this / are confident that the Revealer may reveal something of value