Learn Hardcore Spanish (Latin America): A veces suceden cosas inesperadas cuando menos las esperas. - Sometimes unexpected things happen when you least expect them.

The subject here is cosas inesperadas, which is plural, so the verb must agree in number and use the third-person plural form suceden. If it were a singular noun, you would use sucede.

Why do we see las in cuando menos las esperas?

The pronoun las refers back to the plural feminine noun cosas inesperadas. In Spanish, object pronouns must agree in gender and number with the noun they replace.

What does inesperadas agree with in this sentence?

It agrees with cosas, which is feminine and plural. Hence, the adjective inesperadas is also feminine and plural.

What is the role of cuando menos las esperas in the sentence?

It’s a time/clause expression meaning when you least expect them. It indicates the moment in which these unexpected things happen, emphasizing the element of surprise.

Can you use another expression instead of A veces to begin the sentence?

Yes. You could say Algunas veces, which also means sometimes. However, A veces is more idiomatic and widely used in everyday speech.