Dnes jsme sklidili úrodu, což je dobrá zpráva.

In Czech, the past tense is usually made with:

• the past participle of the main verb
• plus a short form of to be

So jsme sklidili means literally something like we have harvested / we harvested.

Here:

• jsme = we are / we have auxiliary used for past tense
• sklidili = past participle of sklidit (to harvest, to gather in)

This is the normal Czech way to say we harvested.

The ending -i shows that the subject is we and that the group is masculine animate or mixed, or it can sometimes be used in standard teaching examples as the default plural form learners first notice.

More broadly, Czech past participles change according to gender and number:

• sklidil = he harvested
• sklidila = she harvested
• sklidilo = it harvested
• sklidili = they/we harvested (masculine animate or mixed group)
• sklidily = they/we harvested (non-masculine animate group)

In this sentence, sklidili tells you the speaker is part of a plural subject: we.

Dnes means today.

Czech word order is more flexible than English, so Dnes can move, but the emphasis changes. For example:

• Dnes jsme sklidili úrodu. = neutral, Today we harvested the crop.
• Úrodu jsme dnes sklidili. = puts more focus on the crop
• Sklidili jsme dnes úrodu. = possible, with a different rhythm/emphasis

The sentence you have is a very natural, neutral way to say it.

Because úroda is the direct object of the verb sklidit, so it must be in the accusative case.

• nominative: úroda = the harvest / crop as a subject
• accusative: úrodu = the harvest / crop as an object

Compare:

• Úroda je dobrá. = The harvest is good.
  (úroda is the subject)
• Sklidili jsme úrodu. = We harvested the harvest/crop.
  (úrodu is the object)

So the -u ending is required by the grammar.

Sklidili comes from sklidit, which usually means to harvest, to gather in, or to bring in a crop.

It is more specific than a general verb like sbírat (to pick / collect) and often fits agriculture especially well.

A rough comparison:

• sklidit úrodu = to harvest the crop
• sbírat ovoce = to pick fruit / collect fruit
• sebrat = to pick up / collect / gather, often more general

So sklidili úrodu is the natural collocation for harvesting.

Což means something like which, and that, or which is, referring back to the whole previous idea.

In this sentence:

• Dnes jsme sklidili úrodu, což je dobrá zpráva.

the word což refers to the entire fact that we harvested the crop today.

So the second part means:

• which is good news

This is different from referring to just one noun. It points back to the whole preceding statement.

Because což is the normal choice when you refer back to a whole clause or whole situation.

• což = refers to the whole previous statement
• který / která / které = usually refers to a specific noun

Here the speaker is not saying that one noun, such as úroda, is good news. The speaker is saying that the fact that we harvested the crop today is good news.

So:

• Dnes jsme sklidili úrodu, což je dobrá zpráva. = correct and natural

Using které here would sound wrong to most learners and in standard usage would not be the right relative connection for the whole clause.

Because zpráva is a feminine singular noun, and the adjective must agree with it.

• zpráva = feminine singular nominative
• therefore dobrá = feminine singular nominative form of dobrý

So:

• dobrá zpráva = good news

Czech adjectives agree with the noun in:

• gender
• number
• case

That is why the adjective changes form.

Yes. In Czech, zpráva is a normal singular countable noun meaning report, message, piece of news, and in many contexts good news / bad news is expressed with singular zpráva.

So:

• To je dobrá zpráva. = That is good news.

English news is grammatically singular but looks plural; Czech does not work the same way here. Czech simply uses the singular noun zpráva.

Sklidit is a perfective verb.

That matters because perfective verbs present the action as completed. In this sentence, the harvesting is viewed as finished:

• Dnes jsme sklidili úrodu. = Today we finished harvesting the crop / we harvested the crop

The imperfective partner is usually sklízet:

• Dnes jsme sklízeli úrodu. = Today we were harvesting the crop / harvested the crop as an ongoing activity

So the original sentence emphasizes a completed result, which fits well with that’s good news.

Grammatically, Czech past tense does not match English tenses one-to-one.

Dnes jsme sklidili úrodu can often be translated as:

• Today we harvested the crop
• or sometimes Today we’ve harvested the crop

Which English version sounds best depends on context and natural English style. In most everyday English, Today we harvested the crop is usually the most straightforward translation.

So Czech past tense here does not force one specific English tense.

Yes, in standard Czech punctuation, a comma is used before což here because it introduces a subordinate/relative clause referring back to the previous statement.

So the correct punctuation is:

• Dnes jsme sklidili úrodu, což je dobrá zpráva.

The comma should not be omitted in careful written Czech.

Normally, no, not in standard Czech past tense.

In present tense, Czech often drops subject pronouns like my (we) because the verb ending already shows the person. But in the past tense, the auxiliary jsem, jsi, jsme, jste is part of the verb form itself.

So:

• Dnes jsme sklidili úrodu. = correct
• Dnes sklidili úrodu. = means They harvested the crop today, not we harvested

So jsme is not optional here if you mean we.

Because Czech usually does not need the personal pronoun when the verb already makes the subject clear.

• jsme already tells you the subject is we
• adding my is possible, but it adds emphasis or contrast

Compare:

• Dnes jsme sklidili úrodu. = neutral Today we harvested the crop
• Dnes jsme my sklidili úrodu. = It was we who harvested the crop today
• My jsme dnes sklidili úrodu. = emphasized we

So the version without my is the normal neutral one.