Learn Spanish (Latin America): Me alivia que ellos se hayan abrochado el cinturón durante el despegue. - It relieves me that they have fastened their seatbelts during the takeoff.

Me alivia que ellos se hayan abrochado el cinturón durante el despegue.

It relieves me that they have fastened their seatbelts during the takeoff.

Breakdown of Me alivia que ellos se hayan abrochado el cinturón durante el despegue.

to me / me (direct object)

haber

(auxiliary) have

Questions & Answers about Me alivia que ellos se hayan abrochado el cinturón durante el despegue.

Why do we use the present perfect subjunctive (hayan abrochado) here instead of the present subjunctive (abrochen)?

We use the present perfect subjunctive because the action of fastening the seatbelt happened before the present emotion. Me alivia (present tense) expresses how you feel right now about something they have already done (hayan abrochado).

What exactly triggers the subjunctive in the second half of this sentence?

The phrase Me alivia que (It relieves me that) expresses an emotion or a personal reaction. Whenever you express a feeling about someone else's action using que, the following verb must be in the subjunctive.

Why is it el cinturón (singular) when the English translation says "their seatbelts" (plural)?

In Spanish, when a group of people each has one of the same item (like a seatbelt, a nose, or a shirt), you usually use the singular noun. Saying los cinturones might imply that each person fastened multiple seatbelts!

Why do we need the pronoun se before hayan abrochado?

The verb here is abrocharse (to fasten upon oneself). The se shows that they fastened the seatbelts on their own bodies. Without se, abrochar just means to fasten something in general, like a strap on a backpack.