There are three completely irregular verbs in the subjunctive. They are 'ir', to go; 'ser', to be; and 'ver', to see. So, for 'ir' you have: vaya, vayas, vaya, vayamos, vayáis, vayan. For 'ser' you have: sea, seas, sea, seamos, seáis, sean. And for 'ver' you have vea, veas, vea, veamos, veáis, vean. Now, here are some examples of requests, suggestions, invitations, or refusals using the subjunctive. Quiero que me traigas otro café - I want you to bring me another coffee. You see, this is a request and it's a very polite way to do it. Another example. Mi profesor nos sugiere que hagamos la tarea a tiempo - My professor suggests that we do our homework on time. So, it's like a command but we'll call it a suggestion. Here's another one. Es necesario que veamos la carta primero - We have to see the menu first. This is clearly a request to have someone bring you the menu. Let's look at an invitation. Te invitamos a que comas en casa - We would like to invite you to eat at our house, to dine at our house. So that's an invitation. Te pido que no vayas a otro restaurante - I'm asking you please not to go to another restaurant. So that's a request. Another example. Mis padres prefieren que el cocinero no les ponga mucha sal en la comida - My parents prefer that the chef doesn't put a lot of salt on the food. That's obviously a request or a command but again, it's a softened command. Another example. No permito que me lleves a ese restaurante - I won't allow that you take me to that restaurant. So that's clearly a refusal but in a way it's a negative command. One final example. Es preciso que salgamos de aquí inmediatamente - We have to leave this restaurant right now. So, it's like a command or a suggestion. As you can see, in all of these cases, the subjunctive is being used in lieu of using direct commands. Why? Because it's slightly more polite.