Il cane corre sulla sponda del fiume.

In Italian, the definite article for masculine singular nouns starting with a simple consonant (like c in cane) is il.

• lo is used only before certain consonant clusters (z, s + consonant, gn, ps, x, y, etc.), for example lo zaino, lo studente.
  Since cane begins with a single consonant + vowel, the correct form is il cane.

Sulla is the contraction of the preposition su (“on”) plus the feminine singular definite article la. In Italian, some prepositions automatically combine with articles:

• su + il = sul
• su + la = sulla
• su + l’ = sull’
• su + lo = sullo
• su + i = sui
• su + gli = sugli
• su + le = sulle

When the preposition di (“of”/“from”) meets the masculine singular article il, they fuse into del. So:

• di + il fiume → del fiume
  You cannot say di il fiume in standard Italian.

Italian verbs change their endings depending on person and number. For correre (to run) in the present tense:

• io corro
• tu corri
• lui/lei corre
• noi corriamo
• voi correte
• loro corrono
  Since il cane is “he/it,” we use corre.

In Italian, adverbial expressions of place usually follow the verb:

• Il cane corre sulla sponda del fiume.
  You can front it for emphasis—Sulla sponda del fiume corre il cane—but the neutral, default order is subject–verb–place.

Both mean “bank” or “shore,” but:

• sponda often implies the sloping side or embankment of a river.
• riva is more general and can refer to the edge of any body of water (lake, sea, river).
  In many contexts they’re interchangeable, but sponda has a slightly more technical or geomorphological feel.