Question 1 Jaime lee un libro.
Answer 1 Jaime lo lee. (Libro is a masculine subject, so pronoun must be masculine, too)
Question 2 Los niños comen frutas.
Answer 2 Los niños las comen. (Frutas is a feminine plural subject, so pronoun must be feminine plural, too)
Question 3 Tanya know me from school.
Answer 3 Tanya me conoce. (me = a mí)
Question 4 They see Annie.
Answer 4 Ellos la ven. (Annie is a feminine subject, so pronoun must be feminine, too)
Question 5 She buys milk at the store.
Answer 5 Ella la compra. (Milk is a feminine subject, so pronoun must be feminine, too)
Hope this helps!