Learn Hardcore Portuguese (Portugal): Durante a pandemia, aprendemos a valorizar mais a ciência e os cientistas. - During the pandemic, we learned to value science and scientists more.

Durante a pandemia = during the pandemic, focusing on the time span in which something happened.
Na pandemia = literally in the pandemic, and sounds less natural here; it tends to be used more when you’re categorising a period (e.g. na pandemia, no pós‑guerra, no verão), but even then durante a pandemia is still the more idiomatic choice to express “while the pandemic was going on”.

In this sentence, we’re clearly talking about something that happened over the course of that period, so durante is the best choice.

Which tense is aprendemos here: present or past?

For regular ‑er verbs like aprender, nós aprendemos is the same form in the present and in the preterite (simple past).

Present: (agora) nós aprendemos = we learn / we are learning
Preterite: (ontem) nós aprendemos = we learned / we have learned

In this sentence, Durante a pandemia gives a past time frame, so aprendemos is understood as simple past: we learned. Context usually disambiguates.

Why do we say aprendemos a valorizar and not just aprendemos valorizar?

In Portuguese, aprender normally takes the preposition a before an infinitive:

aprender a ler – to learn to read
aprender a cozinhar – to learn to cook
aprender a valorizar – to learn to value / appreciate

Saying aprendemos valorizar (without a) is ungrammatical in standard Portuguese. Think of aprender a + infinitive as one fixed pattern.

What exactly does valorizar mean here? Is it just “to value”?

Valorizar can mean:

to value, appreciate, recognise the importance of
to enhance, add value to, make something more valuable (e.g. valorizar um imóvel – to increase the value of a property)

In this sentence, it means to appreciate / to recognise the importance of science and scientists. Translating as we learned to value / appreciate science and scientists more captures the idea.

Why is mais placed before a ciência, and can we move it?

Here, mais modifies valorizar (how much we value), not ciência specifically, so it normally goes right after the infinitive:

aprender a valorizar mais a ciência = learn to value science more

You could say aprender a valorizar a ciência mais, and people would understand, but valorizar mais a ciência is more natural and keeps mais closer to the verb it modifies. If you moved mais to the very beginning (mais valorizamos a ciência), the structure and nuance of the sentence would change.

Why do we say a ciência with the article, when in English we just say “science”?

Portuguese uses the definite article much more than English, including:

with abstract nouns: a ciência, a liberdade, a educação
with general categories: a música clássica, o vinho, os cães

So a ciência here means science in general, not “a specific science”. English normally drops the article in that case (we value science), but in Portuguese a ciência is the natural choice. Omitting the article (valorizar ciência) sounds incomplete or telegraphic.

Why do we say os cientistas and not just cientistas?

Again, Portuguese tends to use the article when talking about a group in general:

os cientistas = scientists as a group, in general
bare cientistas (without an article) is possible in some structures, but often sounds incomplete or more like a role label (e.g. in headlines or lists).

In a normal sentence, a ciência e os cientistas is the idiomatic way to say science and scientists (in general).

Does os cientistas include women, or would we need as cientistas?

The noun cientista itself is invariable in form (ending in ‑a for both genders), and the article shows the gender:

o cientista = the male scientist
a cientista = the female scientist
os cientistas = a mixed or all‑male group
as cientistas = an all‑female group

In this sentence, os cientistas is the standard generic plural, which in Portuguese is masculine and is understood to include both men and women unless you specify otherwise.

Why is pandemia feminine (a pandemia)?

Many Portuguese nouns ending in ‑ia are feminine, especially abstract ones:

a democracia, a filosofia, a biologia, a economia, a pandemia

There’s no special rule just for pandemia; it follows this broad pattern. So you say a pandemia, durante a pandemia, depois da pandemia, etc.

Could we say Durante a pandemia, temos aprendido a valorizar… instead of aprendemos?

Yes, but the nuance changes:

aprendemos (simple past) suggests something more completed or viewed as a finished learning process during that period.
temos aprendido (present perfect) highlights an ongoing process up to now: we have been learning to value…

In European Portuguese, temos aprendido is used for “have been learning” (repeated/ongoing up to the present), so it would imply the learning is still in progress. The original aprendemos treats it more as a lesson learned during that time.

Could we use para instead of a: aprendemos para valorizar mais…?

No, not in this structure.

aprender a + infinitive = to learn to do something
aprender para + infinitive usually doesn’t work; para here would sound like a purpose clause (learn in order to value), but that’s not how Portuguese expresses this idea.

To express the English learn to value, the correct and natural pattern is always aprender a valorizar, never aprender para valorizar.

How do you pronounce ciência and where is the stress?

Ciência is stressed on the second syllable: ci‑ÊN‑cia.

ci‑: pronounced like see, but shorter; c before i is /s/, not /k/
‑ên‑: stressed; the ê is a closed e sound, like the e in they but shorter
‑cia: sounds like syah (/sjɐ/ in European Portuguese)

Rough approximation in English: see‑EN‑syah, with the EN part stressed.