Repare que o verbo auxiliar vem antes do sujeito.
1 Conditional (Type 1):
- Should you need anything, do not hesitate to ask.
(=If you should need ...)
- Se precisar de alguma coisa, não hesite em pedir.
- Should you be late for the meeting, please give me a call.
(=If you should be ...)
- Se chegar atrasado à reunião, telefone-me por favor.
2 Conditional (Type 2):
- Were you to interview him, what would you ask?
(=If you were to interview ...)
- Se o fosse entrevistar, o que lhe perguntaria?
- Were you at home right now, what would you be doing?
(=If you were ...)
- Se estivesse em casa agora mesmo, o que estaria a fazer?
3 Conditional (Type 3):
- Had he studied, he would have passed the exam.
(=If he had studied ...)
- Se ele tivesse estudado, teria passado no exame.
- Had he told us he was coming, we would have waited for him.
(=If he had told ...)
- Se ele nos tivesse dito que vinha, teríamos esperado por ele.