Caementum canalem obstruit.

A rubble stone clogs the conduit.

Breakdown of Caementum canalem obstruit.

• canalis: the masonry water conduit
• caementum: a rubble stone (rough, uncut)
• obstruere: to clog; stop up

Questions & Answers about Caementum canalem obstruit.

How do I know which word is the subject and which is the object?

You can tell mainly from the endings.

• caementum is nominative singular, so it is the subject
• canalem is accusative singular, so it is the direct object

So the sentence means that caementum is doing the action, and canalem is receiving it.

Even though English relies heavily on word order, Latin relies much more on case endings.

Why does canalem end in -em?

Because it is the accusative singular form of canalis.

This noun belongs to the third declension, and many third-declension nouns form the accusative singular with -em.

So:

• nominative: canalis
• accusative: canalem

Here, the verb obstruit takes a direct object, so canalis has to appear in the accusative: canalem.

Why does caementum end in -um? Is that also accusative?