Dok je zemlja mokra, lakše je čupati korov.

Here dok means while or when in the sense of while/as long as the ground is wet.

A few useful notes:

• dok often introduces a time clause.
• In other contexts, it can also mean while in a contrastive sense, but here it is purely temporal.
• So Dok je zemlja mokra means something like While the soil is wet / When the ground is wet.

Because the sentence has two separate parts, and each needs its own verb:

1. Dok je zemlja mokra

   • je = is
   • literally: While the ground is wet

2. lakše je čupati korov

   • je is again the verb is
   • literally: it is easier to pull weeds

So the two je forms belong to two different clauses.

Because mokra must agree with zemlja.

• zemlja is a feminine singular noun
• adjectives must match the noun in gender, number, and case
• so the adjective must also be feminine singular: mokra

Comparison:

• mokar = masculine singular
• mokra = feminine singular
• mokro = neuter singular

Since zemlja is feminine, mokra is the correct form.

Lakše is the comparative form of lako.

• lako = easily / easy
• lakše = more easily / easier

In this sentence, Croatian uses an impersonal structure:

• Lakše je čupati korov = It is easier to pull weeds

So lakše is functioning like easier in English.

Why not lakši/lakša/lakše as an adjective agreeing with a noun?
Because here it is not describing a noun directly. It is part of the impersonal expression lakše je + infinitive = it is easier to...

Because Croatian often uses the pattern:

• je + comparative/adverb + infinitive

So:

• lakše je čupati = it is easier to pull

The infinitive čupati works much like the English infinitive to pull.

This is a very common structure:

• Teško je učiti. = It is hard to study.
• Lako je razumjeti. = It is easy to understand.
• Lakše je čupati korov. = It is easier to pull weeds.

Čupati means to pull out, to yank out, or to uproot, especially something that resists a bit.

So for weeds, it is a very natural verb.

A useful nuance:

• čupati often suggests repeated or effortful pulling
• for weeds, hair, feathers, etc., it is a common verb

Related verbs:

• vući = to pull, in a more general sense
• iščupati / počupati = to pull out completely, often with a sense of completion

So čupati korov is a very natural way to say pull weeds / weed by pulling.

Because korov often works as a collective or mass noun in Croatian, similar to how English can say weed or weeds depending on style.

So:

• čupati korov literally looks like to pull weed
• but naturally it means to pull weeds / to weed

This is normal in Croatian. The singular form can refer to weeds in general, not just one specific weed.

Korov is in the accusative singular, which for many masculine inanimate nouns looks the same as the nominative singular.

Why accusative?

• because it is the direct object of čupati

So:

• nominative: korov
• accusative: korov

There is no visible change here, but grammatically it is accusative.

Because Croatian often uses impersonal constructions without an explicit subject where English uses it.

English says:

• It is easier to pull weeds.

Croatian says:

• Lakše je čupati korov.

That it in English is only a dummy subject. Croatian usually does not need such a word.

So the Croatian sentence is completely normal without any pronoun.

Because Dok je zemlja mokra is a subordinate clause placed before the main clause.

Croatian normally separates that introductory clause with a comma:

• Dok je zemlja mokra, lakše je čupati korov.

This is similar to English writing:

• When the ground is wet, it is easier to pull weeds.

So the comma marks the boundary between:

• the time clause
• the main statement

Yes. Croatian word order is fairly flexible, though some versions sound more natural than others.

The given sentence is very natural:

• Dok je zemlja mokra, lakše je čupati korov.

You could also say:

• Lakše je čupati korov dok je zemlja mokra.

That puts the main idea first and the time clause second.

Both are correct. The difference is mostly about emphasis:

• Dok je zemlja mokra, ... = emphasizes the condition/time first
• Lakše je čupati korov ... = emphasizes the main point first

In this sentence, zemlja means soil/ground/earth in the gardening sense.

Croatian zemlja can mean several things depending on context:

• earth / soil
• ground
• even country/land in some contexts

Here, because of mokra and čupati korov, the meaning is clearly soil/ground.

Yes. Čupati is imperfective, and that fits the general meaning of the sentence.

The sentence is not about one single completed action. It expresses a general truth:

• When the ground is wet, pulling weeds is easier.

That is why imperfective čupati works well.

If you used a perfective verb such as počupati or iščupati, the meaning would shift toward pulling them out completely in a more result-focused way.

So:

• čupati korov = to pull weeds / to be pulling weeds, generally
• počupati korov = to pull out the weeds completely

In this sentence, the imperfective is the more natural choice.