Although que is most often used as a relative pronoun, it is also frequently used as a subordinating conjunction.

The distinction may not seem obvious to English speakers, because que in both cases is usually translated as "that." However, the distinction is important in some situations, such as those listed below when translating "that" after a noun.

Que is used as a conjunction in the following sentence construction:

• Main or independent clause + que + dependent clause.

The main clause includes a subject and verb, although the subject may be understood rather than explicitly stated. The dependent clause also has a subject and verb (although the subject again may be implied) and could stand alone as a sentence, but it depends on the main clause to indicate its significance.

The usage is similar in English:

• Main clause + "that" as a conjunction + dependent clause.

The main difference is that in English it is common to omit "that," while que is nearly always mandatory.

A simple example should make this clearer. In the sentence "Olivia sabe que Francisco está enfermo" (Olivia knows that Francisco is sick), "Olivia sabe" (Olivia knows) is the main clause, que is a conjunction, and "Francisco está enfermo" (Francisco is sick) is the dependent clause. Note that "Olivia sabe" and "Francisco está enfermo" each has a subject and verb.

Here are some other examples of que as a conjunction:

• Todos creemos que fue un asesinato. We all believe (that) it was a murder.

• Esperamos que este fin de semana sea más productivo. We are hoping (that) this weekend will be more productive.
• Quiero que me quieras. I want you to love me. (Literally, I want that you love me.)
• No creí que fuera fisicamente posible. I didn't believe (that) it was physically possible.
• Predigo que la banca móvil expandirá en el futuro. I predict (that) mobile banking will expand in the future.

If the main clause ends in a noun, de que is used as a conjunction instead of que:

• Tengo el miedo de que sea un virus. I am afraid (that) it is a virus.
• ¿Tienes celos de que Andrew pase tiempo con Lauren? Are you jealous (that) Andrew is spending time with Lauren?
• Hizo el anuncio de que el primer sencillo de su segundo álbum se llamaría «Move». He made the announcement (that) the first single from his second album would be called "Move."

Note, however, that when que is used as a relative pronoun after a noun, de que cannot be used. An example: Hizo an anuncio que nos sorprendió. He made an announcement that surprised us.

One way whether you can tell that que in the above example is a relative pronoun is that you could translate it as "which" and still make sense (i.e., he made an announcement which surprised us). But in the examples above where de que is used, "that" and not "which" must be used in translation.

When a verb or a phrase is commonly followed by de and an infinitive or noun, often de que followed by a clause can be used instead:

• Nunca me canso de que digan que soy guapo. I never tire of them saying (that) I am handsome.
• Estamos felices de que haya boda. We are happy (that) there was a wedding.
• No me olvidó de que la literatura puede servir de entretenimiento. I didn't forget (that) literature can serve as entertainment.

Sources: Sample sentences have been adapted from sources that include Larzon.es, Meridiano.com.ve, Jesse y Joy, Facebook conversations, Spanish for Business Professions, Psicología Online, Tumblr.com, NorAm Construction, es.Wikipedia.org, Letra Libres, and Europa Press.