Word classes in English have specific functions, being essential for the correct construction and interpretation of sentences. Thus, analyze the following statements:

I.Personal pronouns in English can be used as subjects or objects, depending on their position in the sentence.
II.Adjectives in English usually precede the nouns they describe, as in "a small house."
III.Uncountable nouns in English, such as "water" and "information," can be made plural by adding "-s."

The correct statements are: