It means "when".
cuando hay clase = when class hay = there is/are cuando = when clase = class
As a question ¿Cuando vienes? means "When are you coming?"
When.
"Cuando llama" in English means "When she calls."
"Cuando tengo" translates to "when I have" in English.
If you mean 'When I arrive' - Cuando llegare If you mean 'When I'm in that place' - Cuando estoy alli.
"Cuando llegan" means "when they arrive". "¿Cuándo llegan?" means "when do they arrive?"
"Cuando vuelvas" means "when you come back" in English.
"When, friend?"
Cuando can either mean 'when' or 'since' depending on the condition of expression. An example of using cuando as 'when' is, "Cuando me llamas, te diré" (When you call me, I will tell you.) An example of using cuando as 'since' is "No sé por qué estás haciendo compras cuando no tienes dinero" (I don't know why you are shopping when/since you have no money).
it means "when were you born"
¿Cuando vas tú a la fiesta?When are you going to the party?