Polyketide
聚酮化合物
🗣️ 情景例句
He missed a phone call.
他没接到一通电话。
He has been working in advertising for ten years, but now he is teaching.
他曾经在广告公司服务十年，但现在在当老师。
This is because the surface of the earth is not flat but round.
因为地球表面不是平的，而是圆的。