Haec res parva videtur, sed magnam partem diei capit.

Because res is a feminine singular noun in the nominative case, and haec is the matching feminine singular form of hic, haec, hoc (this).

So:

• haec = this (feminine nominative singular)
• res = thing, matter, affair (feminine nominative singular)

They must agree in gender, number, and case.

That is why Latin says haec res for this thing.

Res is nominative singular because it is the subject of the sentence.

The sentence is about this thing:

• Haec res parva videtur = This thing seems small

So res is the thing doing the “seeming,” and subjects go in the nominative.

Parva is an adjective meaning small, and it agrees with res.

Since res is:

• feminine
• singular
• nominative

the adjective must also be:

• feminine
• singular
• nominative

So:

• res parva = a small thing
• haec res parva = this small thing

In the sentence, parva works with videtur:

• haec res parva videtur = this thing seems small

Yes—literally, videtur is the passive form of video, so it can mean is seen.

But in Latin, videtur is also very commonly used in the sense of seems or appears.

So:

• parva videtur = it seems small
• literally something like it is seen as small

This is a very normal Latin idiom, and learners meet it often.

Because est parva and parva videtur do not mean exactly the same thing.

• est parva = it is small
• parva videtur = it seems small / it appears small

So videtur adds the idea of appearance or impression, not simple fact.

That distinction matters here, because the sentence contrasts appearance with reality:

• It seems small
• but it takes up a large part of the day

This phrase means a large part of the day.

It has two main pieces:

• magnam partem = a large part

  • partem is accusative singular of pars
  • magnam agrees with partem

• diei = of the day

  • genitive singular of dies

So literally:

• magnam partem diei = a large part of the day

This whole phrase is the object of capit.

Because Latin often uses the genitive to show the whole of which something is a part.

So:

• partem diei = part of the day
• not part the day

This is often called a partitive genitive or genitive of the whole.

English also uses of here:

• a part of the day

Latin expresses that of the day idea with the genitive diei.

Here capit means takes up, occupies, or consumes.

It comes from capio, capere, whose basic meaning is take, but in context it can mean things like:

• take
• hold
• contain
• occupy
• take up

So:

• magnam partem diei capit = it takes up a large part of the day

This is a very natural Latin use of capere.

Because it is the direct object of capit.

The verb capit is transitive here: it takes something.
What does it take up?

• magnam partem diei

The core accusative noun is partem, and magnam agrees with it.

So:

• capit partem = it takes a part
• capit magnam partem diei = it takes up a large part of the day

Yes, Latin word order is much more flexible than English word order.

The sentence as given is:

• Haec res parva videtur, sed magnam partem diei capit.

This is a very natural order, but other orders would still be grammatical because the endings show the relationships.

For example, Latin can move words for emphasis:

• Parva haec res videtur
• Magnam diei partem capit

The given version is clear and fairly straightforward:

• subject first: haec res
• description before the verb: parva
• verb at the end of the clause: videtur
• then the contrasting clause with sed

That final position for the verb is especially common in Latin.

Res is a very common Latin noun with a broad meaning. Depending on context, it can mean:

• thing
• matter
• affair
• business
• situation
• fact

Here, thing is a perfectly good translation, but the Latin word is more flexible than English thing. It often refers to almost any matter or issue being discussed.

So haec res could be understood as:

• this thing
• this matter
• this issue

depending on context.

Sed means but, and it marks a contrast between the two clauses:

• Haec res parva videtur = This thing seems small
• sed magnam partem diei capit = but it takes up a large part of the day

So the sentence sets up an opposition between:

• appearance: seems small
• reality/effect: takes a lot of time

This kind of contrast is exactly what sed is used for.

Yes. The subject is still haec res, even though Latin does not repeat it.

So the full sense is:

• Haec res parva videtur, sed [haec res] magnam partem diei capit.

Latin often leaves out a repeated subject when it is clear from context.

English does the same sometimes, but usually we would still say it:

• This thing seems small, but it takes up a large part of the day.