Las expresiones

This is / These are

se utilizan para presentar a alguien. Mira el ejemplo del Diálogo 1 (Red Book)

MONICA: Jaime, this is my friend, Sara, she’s my room-mate. JAIME: How do you do, Sara? O: MONICA: Jaime, this is Sara, she’s my room-mate. JAIME: How do you do, Sara?

 La expresión ‘This is’ se utiliza para presentarle una persona a otra. Veamos más ejemplos:

Mary to Tom: (Mary presentando a su hijo (son) Paul)

Tom, this is my son, Paul.  Tom, this is Paul, my son.

Jerry to Louise: (Jerry presentando a su esposo (husband) Charles)

Louise, this is my husband, Charles. Louise, this is Charles, my husband.

Jack to Max: (Jack presentando a su padre (father) Ryan)

Max, this is my father, Ryan. Tom, this is Ryan, my father.