Curator altitudinem et longitudinem metitur.

Because metitur comes from a deponent verb: metior, metiri, mensus sum.

Deponent verbs use passive-looking forms but have active meanings. So:

• metitur looks like a passive form
• but it actually means he measures, she measures, or it measures

So in this sentence, metitur is not passive.

Metitur is:

• third person singular
• present tense
• indicative mood

So it means he/she measures or is measuring, depending on context.

The -tur ending tells you it is third person singular in the present system of a deponent verb.

Curator is in the nominative singular, which is the case normally used for the subject of a sentence.

So curator is the one doing the action of metitur.

A learner may also notice that the verb is third person singular, which matches a singular subject like curator.

They are both in the accusative singular because they are the direct objects of metitur.

The person measures what?

• altitudinem = the height
• longitudinem = the length

Their dictionary forms are:

• altitudo
• longitudo

These are third-declension nouns, and their accusative singular ends in -inem:

• altitudo → altitudinem
• longitudo → longitudinem

Because the verb metitur can take more than one direct object when someone is measuring more than one thing.

Here, the curator measures:

• the height
• and the length

So both nouns are direct objects joined by et.

Et simply means and.

It links the two objects:

• altitudinem
• longitudinem

So the sentence says that both things are being measured.

Yes. Latin word order is much more flexible than English word order because the endings show each word’s role.

So these could still mean the same thing:

• Curator altitudinem et longitudinem metitur
• Altitudinem et longitudinem curator metitur
• Metitur curator altitudinem et longitudinem

The original order is perfectly normal, but Latin does not rely on word order as heavily as English does.

Latin usually does not have definite or indefinite articles.

So curator can mean:

• the curator
• a curator

And altitudinem can mean:

• the height
• a height

The exact sense depends on context.

• curator is a second-declension masculine noun
• altitudo is a third-declension feminine noun
• longitudo is a third-declension feminine noun

More specifically:

• curator, curatoris
• altitudo, altitudinis
• longitudo, longitudinis

A learner should notice that altitudo and longitudo belong to the kind of third-declension nouns whose accusative singular ends in -inem.

Yes. They are closely related to English words:

• altitudo → altitude
• longitudo → longitude

That does not mean the Latin words always match every modern English use exactly, but the connection is very helpful for remembering them.

The principal parts are:

• metior
• metiri
• mensus sum

These tell you that it is a deponent verb and help you recognize its forms.

From these principal parts, you can see why metitur belongs to a verb that looks passive in form but is active in meaning.