Mater ad forum ambulatura est, sed pluvia gravis cadit.

Ambulatura est is a future active participle plus a form of esse (to be).

• ambulatura = about to walk / going to walk
• est = is

So together it means something like:

• she is going to walk
• she is about to walk

This is a common Latin way to express an action that is expected or intended in the near future. It is slightly different in feel from a simple future like ambulabit (she will walk), which is more neutral.

Because it has to agree with mater.

Mater is:

• feminine
• singular
• nominative

So the participle must also be:

• feminine
• singular
• nominative

That gives ambulatura.

If the subject were masculine, you would get ambulaturus. If it were neuter, ambulaturum.

Yes. Mater ad forum ambulabit would also be correct and would mean Mother will walk to the forum.

The difference is nuance:

• ambulabit = simple future, more straightforward
• ambulatura est = is going to walk / is about to walk, often suggesting intention or something expected soon

So ambulatura est can feel a bit more vivid or immediate.

Because ad means to / toward, and it is commonly used with the accusative to show motion toward a place.

So:

• ad forum = to the forum

This is different from location:

• in foro = in the forum or at the forum
• ad forum = to the forum

Latin is very careful about distinguishing movement toward a place from being in a place.

Because forum is a second-declension neuter noun.

For second-declension neuter nouns:

• nominative singular = -um
• accusative singular = -um

So the nominative and accusative singular are identical.

That means:

• forum can be nominative singular
• forum can also be accusative singular

In this sentence, it is accusative because ad takes the accusative.

It is related, but in Latin forum usually means the marketplace, public square, or civic center of a town.

So in this sentence, ad forum means to the forum, that is, to the public square/market area.

The English word forum comes from this Latin word, but in modern English it often has a more abstract sense, like a place for discussion.

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

So Latin often leaves definiteness to context.

For example:

• mater can mean mother, a mother, or the mother
• forum can mean forum, a forum, or the forum

In a sentence like this, English naturally translates them with the if the context makes them definite.

Both word orders are possible in Latin.

Latin word order is much freer than English word order because the endings show how the words fit together. So both of these can mean heavy rain:

• pluvia gravis
• gravis pluvia

The choice is often about style or emphasis rather than basic grammar.

In this sentence, pluvia gravis simply presents the noun first and then describes it.

Because the adjective must agree with pluvia in:

• gender
• number
• case

Pluvia is:

• feminine
• singular
• nominative

So the adjective must also be feminine singular nominative. For gravis, that form is gravis.

Compare:

• gravis = nominative singular masculine/feminine
• grave = nominative/accusative singular neuter
• gravem = accusative singular masculine/feminine

So pluvia gravis is the correct match.

Yes. Latin present tense often covers both:

• falls
• is falling

So cadit can be translated either way depending on context.

In English, heavy rain is falling sounds more natural than heavy rain falls in many contexts, but Latin does not need a separate progressive form here.

So:

• cadit = falls / is falling

It is understandable and perfectly possible, but it is more vivid and concrete than the most basic way.

A very common Latin way to say it is raining is:

• pluit

That is an impersonal verb meaning it rains / it is raining.

By saying pluvia gravis cadit, the sentence focuses on the heavy rain itself as something literally falling. It can sound more descriptive.

Because Latin word order is flexible, and verbs often come near the end of a clause.

So:

• Mater ad forum ambulatura est

is completely normal Latin word order.

Latin relies much more on word endings than on strict word order. English would usually keep the verb earlier, but Latin can move words around for style, rhythm, or emphasis without changing the basic meaning.

It has two main clauses joined by sed (but).

First clause

Mater ad forum ambulatura est

• Mater = subject, Mother
• ad forum = to the forum
• ambulatura est = is going to walk

Second clause

sed pluvia gravis cadit

• sed = but
• pluvia gravis = heavy rain
• cadit = falls / is falling

So the structure is:

• [Mother is going to walk to the forum]
• but
• [heavy rain is falling]

That contrast is what sed is marking.