Copulas
n. 系动词（如be,seem,appear等）, （命题主词与谓词间的）连系( copula的复数形式 )
🗣️ 情景例句
Tom is studying photography at NYU. Tom
正在NYU学摄影。
Track 4 at 9:30.
9点30分，4轨道的车。
suggested an idea on which he had been working for many years to the British Government and industrial circles.
他向英国政府和工业界提出了他研究多年的一项计划。