Linking verb
n. 连系动词（如be, seem, become）
🧩 词语组成解析
[计] 连接, 链接
🗣️ 情景例句
have been busy at work this morning
一早上都在忙着
First come, first served.
捷足先登。
Jim, how long have you been at this school?
吉姆，你到这学校有多么时间了？