Questions & Answers about La dama, la cual llegó tarde, es mi tía.
Why is la cual used here instead of just que?
In Spanish, que is the most common word for 'who' or 'which', so saying La dama, que llegó tarde... is perfectly correct and very common. However, el cual (and its forms like la cual) is a more formal relative pronoun. It is often used in writing or formal speech to add elegance, or to avoid confusion when a sentence has multiple nouns.
How do I know whether to use el cual, la cual, los cuales, or las cuales?
The relative pronoun must match the gender and number of the noun it refers back to. Since it refers to la dama (a feminine, singular noun), it becomes la cual. If we were talking about a group of men (los caballeros), it would be los cuales.
Are the commas around la cual llegó tarde important?
Yes! The commas show that this is extra, explanatory information about the lady. In Spanish, you generally only use la cual or el cual (when there is no preposition in front of it) if the phrase is set off by commas. If the information was absolutely necessary to identify which lady we meant (which would mean no commas), you would stick to using que.
Why use dama here instead of mujer or señora?