Es or está - that is the question
The difference between the verbs ser and estar is one of the trickiest things in Spanish, as you have to deal with clear and unclear rules. Those that you can logically understand and those that don't have any logical explanation. Honestly, I think that that's precisely the case of expression with ser, estar, adjectives, nouns or adverbs and the conjunction que (which, by the way, are called, the impersonal expressions). There are cases where you have to use ser and others where the use of estar is the correct option, just because.
I like having my notes in order though, which is why I have decided to prepare a list of adjectives + que that require use of ser or estar. Many of them require the use of the subjunctive mode, but this is a horse of a different colour.
A list of Spanish impersonal expressions with the verb ser (adjectives)
| Spanish | English |
|---|---|
| Es necesario que | It is necessary that |
| Es preciso que | It is imperative that |
| Es extraño que | It is strange that |
| Es increíble que | It is incredible that |
| Es ridículo que | It is ridiculous that |
| Es terrible que | It is terrible that |
| Es urgente que | It is urgent that |
| Es posible que | It is possible that |
| Es imposible que | It is impossible that |
| Es probable que | It is probable that |
| Es improbable que | It is improbable that |
| Es aconsejable que | It is advisable |
| Es conveniente que | It is convenient that |
| Es importante que | It is important that |
| Es fundamental que | It is fundamental that |
| Es imprescindible que | It is indispensable that |
| Es interesante que | It is interesting that |
| Es vital que | It is vital that |
| Es lógico que | It is logical that |
| Es frecuente que | It is common that |
| Es natural que | It is natural that |
| Es terrible que | It is terrible that |
| Es fabuloso que | It is fabulous that |
| Es fantástico que | It is fantastic that |
| Es admirable que | It is admirable that |
| Es raro que | It is odd that |
| Es difícil que | It is difficult that |
| Es fácil que | It is easy that |
| Es normal que | It is normal that |
| Es maravilloso que | It is wonderful that |
| Es obligatorio que | It is mandatory that |
| Es bueno que | It is good that |
| Es malo que | It is bad that |
| Es peligroso que | It is dangerous that |
| Es extraño que | It is strange that |
| Es dudoso que | It is unlikely that |
| Es preciso que | It is mandatory that |
| Es absurdo que | It is absurd that |
| Es escandaloso que | It is outrageous that |
| Es indignante que | It is outrageous that |
| Es menester que | It is necessary that |
| Es esencial que | It is essential that |
| Es increíble que | It is incredible that |
| Es preferible que | It is preferable that |
All these expressions require the use of the subjunctive mode form both in affirmative (es fabuloso que) and negative (no es fabuloso que) form.
"¡Es increíble que no lo sepas!"
A list of Spanish impersonal expressions with the verb ser and an adverb
| Spanish | English |
|---|---|
| Es mejor que | It is better that |
| Es peor que | It is worse that |
While using these expressions you always have to remember about the subjunctive mode.
"Es mejor que no lo hagas".
Spanish impersonal expressions with the verb ser and a noun
| Spanish | English |
|---|---|
| Es una pena que | It is a pity that |
| Es una lástima que | It is regrettable that |
| Es pura casualidad que | It is purely accidental that |
| Es hora de | It is time to |
| Es de esperar que | It is expected that |
The same rule here. Depending on a sentence after these expressions, you'll have to use either infinitive or subjunctive mode.
"Es una pena que no puedas venir".
"Ya es hora de acostarse, así que buenas noches".
Spanish impersonal expressions that require indicative or subjunctive mode
| Spanish | English |
|---|---|
| Es cierto que | It is true that |
| Es evidente que | It is evident that |
| Es verdad que | It is true that |
| Es seguro que | It is certain that |
| Es exacto que | It is correct that |
| Es obvio que | It is obvious that |
| Es indudable que | It is unquestionable that |
After these expressions you'll have to use what's called an indicative mode.
"Es obvio que no podemos quedarnos aquí".
| Spanish | English |
|---|---|
| No es cierto que | It is not true that |
| No es evidente que | It is not evident that |
| No es verdad que | It is not true that |
| No es seguro que | It is not certain that |
| No es exacto que | It is not correct that |
| No es obvio que | It is not obvious that |
| No es indudable que | It is not unquestionable that |
| Es incierto que | It is uncertain that |
But after these, the use of the subjunctive mode becomes necessary.
"No es obvio que podamos quedarnos aquí".
Spanish impersonal expressions with the verb estar
| Spanish | English |
|---|---|
| Está claro que | It is clear that |
| Está demostrado que | It has been proven that |
| Está mal visto que | It is considered bad that |
| Está previsto que | It is planned that |
| Está muy bien que | It is very good that |
| Está muy mal que | It is very bad that |
The two first expressions (está claro que, está demostrado) require an indicative mode, whereas the rest of them require the subjunctive.