Learn Spanish (Latin America): Yo no veo muchos árboles.

The singular word is árbol (tree). Because it ends in a consonant (the letter 'l'), Spanish rules say we must add -es to make it plural. If it ended in a vowel, we would just add -s.

Why is there an accent mark on the 'a' in árboles?

The singular word árbol has an accent to show we stress the first part of the word (AR-bol). When we add -es, we add another syllable. We keep the accent mark on the 'á' so the spoken stress doesn't shift to the next syllable.

Why do we use muchos here instead of muchas?

Even though it ends in a consonant and not an 'o', the word árbol is a masculine noun. Because we are talking about plural masculine trees, the descriptive word for 'many' must match it, becoming muchos.

I thought regular verbs drop their ending for yo. Why is the verb veo instead of vo?

The verb ver (to see) is slightly irregular in the yo form. Instead of dropping the entire ending, it keeps the 'e' and adds 'o', making it veo. The other forms, like ves (you see), follow the normal rules.