Di should + verbo cuando algo es buena idea, y shouldn't + verbo cuando no lo es.
should / shouldn't + verbo
You should read this book.
You shouldn't stay up late.
Pruébalo: Man: I don't have much money this month. Woman: You ___ buy lunch every day. Elige lo que dice la mujer. (should / shouldn't / didn't) Respuesta: shouldn't — Comprar el almuerzo todos los días cuesta mucho, así que ella le dice: you shouldn't buy it.
Pedir consejo: Should I …?
Pregunta Should I + verbo cuando quieres un consejo.
Should I wear a jacket?
Pruébalo: Yasmin: ___ study here or at home? Lars: Here. The third floor is really quiet. Elige lo que dice Yasmin. (Should I / Why don't you / Could you) Respuesta: Should I — Yasmin quiere un consejo, así que pregunta Should I study here?
Dar una idea: Why don't you / we …?
Why don't you + verbo le da una idea a otra persona. Why don't we + verbo es una idea para ti y la otra persona.
Why don't you ask your teacher?
Why don't we walk?
Pruébalo: Man: I want to learn to cook. Woman: ___ take a cooking class? Elige lo que dice la mujer. (Why don't you / Why don't I / How about) Respuesta: Why don't you — La clase es una idea de ella para él, así que dice Why don't you take a class?
How about + -ing? (¿qué tal si…?)
How about + verbo-ing propone una idea.
How about watching a movie?
Pruébalo: Woman: What do you want to do on Saturday? Man: ___ going to the beach? Woman: Great idea! Elige lo que dice el hombre. (Are you / How about / Why are you) Respuesta: How about — Ella dice "Great idea!", así que él le está dando una idea: How about going to the beach?
It's a good idea to … (es buena idea…)
It's a good idea to + verbo dice qué es bueno hacer.
It's a good idea to take a map.
Pruébalo: Man: I want to run in the park every morning. Woman: ___ start slowly. Elige lo que dice la mujer. (It's not a good idea to / It's a good idea to / You shouldn't) Respuesta: It's a good idea to — Él apenas está empezando, así que ella dice It's a good idea to start slowly.