She worked from half past seven in the morning until late at night, studying government papers.

老师，until late at night: until 是个介词还是连词，late at night 是副词短语吗？

还是until后面省略了She worked ?

【答】从理解句意的角度，在until 之后视为省略了she worked，是可以的。但语言要求简练，避免重复，所以实际不这样说。