Servus sportam gravem ante ianuam deponit.

Because servus is in the nominative singular, the case normally used for the subject of a sentence.

Also, the verb deponit is third-person singular, so it matches a singular subject such as servus. So servus is the one doing the action.

Because sportam is the direct object: it is the thing being put down.

The dictionary form is sporta, meaning basket. But in this sentence it has to be in the accusative singular, which for a first-declension noun ends in -am:

• nominative: sporta
• accusative: sportam

So sportam means the basket or a basket as the object of the verb.

Because gravem is an adjective describing sportam, and Latin adjectives must agree with the nouns they describe in gender, number, and case.

Here:

• sportam is feminine
• singular
• accusative

So gravis has to become gravem, its feminine accusative singular form.

Even though the dictionary form is gravis, the sentence needs gravem because it matches sportam.

Because it comes after the preposition ante, and ante takes the accusative case.

So:

• ante ianuam = in front of the door

This is different from sportam, which is accusative because it is the direct object.
So both words are accusative, but for different reasons:

• sportam: object of the verb
• ianuam: object of the preposition ante

In this sentence it means in front of the door.

The Latin preposition ante can sometimes correspond to English before, but here the meaning is clearly spatial, not temporal, because the sentence is talking about where the basket is placed.

So ante ianuam deponit means he puts it down in front of the door.

Deponit is:

• present tense
• active voice
• indicative mood
• third person singular

It comes from the verb deponere, meaning to put down, set down, or lay aside.

So deponit means he puts down, she puts down, or it puts down.
Because the subject is servus, here it means he puts down.

Because Latin word order is much more flexible than English word order.

A very common Latin pattern is:

• subject first
• verb last

So Servus sportam gravem ante ianuam deponit is perfectly natural Latin.

English relies heavily on word order to show meaning, but Latin often relies more on word endings. That is why the verb can comfortably come at the end.

Yes, often they can.

For example, these would still basically mean the same thing:

• Servus ante ianuam sportam gravem deponit
• Sportam gravem servus ante ianuam deponit
• Ante ianuam servus sportam gravem deponit

The endings still show the grammatical roles:

• servus = subject
• sportam = direct object
• gravem = adjective describing sportam
• ianuam = object of ante

However, changing the word order can change the emphasis. Latin speakers often move words around to highlight what matters most.

Because Classical Latin does not have articles like English the and a/an.

So a noun like servus can mean:

• a slave / a servant
• the slave / the servant

Likewise sportam can mean:

• a basket
• the basket

Which one is best depends on the context or on how the sentence is translated into English.

Servus most literally means slave, but in some learning materials it may be translated more loosely as servant.

Which English word is best depends on the context:

• in a Roman historical setting, slave is often the most exact meaning
• in simplified beginner material, servant is sometimes used

Grammatically, though, it works the same either way: servus is the male person doing the action.

A good way is to group the sentence like this:

• Servus = the subject
• sportam gravem = the direct object phrase, the heavy basket
• ante ianuam = the prepositional phrase, in front of the door
• deponit = the verb, puts down

So the structure is:

[subject] [object + adjective] [prepositional phrase] [verb]

That makes it easier to read the sentence as Latin instead of translating word by word.