¿Por qué lo necesitan?
Why do you/they need it?47.3 Expressing needs in an impersonal way
To ask and answer questions about needs in an impersonal way, that is, without
reference to a specific person, we use the following expressions.47.3.1 Hay que+ infinitive
Hay que, ‘one needs’ or ‘has to’ is by far the most common expression used in
expressing need in an impersonal way.¿Hay que hacerlo de nuevo?
Does one/do we need to do it again?Hay que estar muy alerta.
One needs to be very alert.Hay que trabajar para vivir.
One needs to work in order to live.To express the need not to do something we use the same expression in a negative
construction, which indicates strong need, closer to prohibition:Aquí no hay que fumar, está prohibido.
You mustn’t smoke here, it’s forbidden.16.1.1.7 (p. 62); 46.3 (p. 274)
47.3.2 Hacer falta+ infinitive
Hacer falta, ‘to be necessary’, is less common than hay que in positive sentences but
very common in negative sentences to express the idea that something is unnecessary.¿Hace falta comprar algo?
Do we need to buy anything?No hace falta traer nada.
We don’t need to bring anything.Hace falta ser muy cuidadoso.
One needs to be very careful.No hace falta preparar más comida. Hay suficiente.
We don’t need to prepare more food. There is enough.Hacer falta is often found by itself in reply to a question or a statement, for example an
offer:¿Quieres que te compre uno?
Shall I buy one for you?
No hace falta, gracias.
There’s no need, thank you.Expressing needs in an impersonal way 47.3