No se puede viajar a ese país hasta que ________ seguro.

Question

I don't understand why this sentence is translated as ... ('we' can't travel). Wouldn't it be podemos for *we* ? I thought *puede* was singular for he/her/it

I also don't understand why the answer is *sea* and not *se*

Can someone please explain.

Accepted Answer

No se puede viajar a ese país - translates as you cannot travel to that country. It's an impersonal sentence. - See lesson - Using se debe/se puede to say You must/you can (impersonal sentences)
 
The reason it is sea is because the phrase 'hasta que' triggers the use of the subjunctive. In this case the present subjunctive of the verb ser. See lesson -  Using adverbial clauses para que, antes (de) que, hasta que, con tal (de) que, etc. + El Presente de Subjuntivo (present subjunctive)