Ten cuidado, no vaya a ser que caiga la trampilla.

Be careful, in case the trapdoor falls.

Breakdown of Ten cuidado, no vaya a ser que caiga la trampilla.

• tener: to have
• ser: to be
• ir: to go
• a: to

Questions & Answers about Ten cuidado, no vaya a ser que caiga la trampilla.

Why is it ten cuidado and not tiene cuidado or tú tienes cuidado?

Ten cuidado uses the tú imperative of tener, so it means be careful.

• tener → ten in the tú command form
• This is an irregular imperative, just like:
  • venir → ven
  • poner → pon
  • hacer → haz

So:

• Ten cuidado = Be careful
• Tiene cuidado would mean he/she is careful or you (formal) are careful, not a command.
• Tú tienes cuidado is a statement, not an instruction.

In Spain, you might also hear:

• Tened cuidado = be careful (addressing vosotros)
• Tenga cuidado = be careful (formal usted)

What exactly does no vaya a ser que mean?