Es un corredor de cambios bien conocido: He is a well-known exchange broker.

Son buenos valores: They are good securities.

2. When "to be" is used to denote possession, as—

Los trapiches son de estos fabricantes: The sugar mills belong to these makers.

3. When "to be" us used impersonally, as—

Es necesario tomar medidas legales: It is necessary to take legal proceedings.

4. Before the words "Feliz," "Infeliz," "Pobre," and "Rico."[117]

[Footnote 117: These are not, strictly speaking, "inherent qualities," but they are spoken of as such.]

Estar must, of course, be always used before Present Participles,[118] as—

Está activando sus esfuerzos: He is making still further efforts.
Estamos extendiendo nuestras relaciones: We are extending our connection.