First, you would need to conjugate preferir.
To do this you would need to remove the -ir and add an e since since it is in present tense and you are speaking for Carlos. This means that it would be in the tú form.
Carlos prefere las papas fritas.
Carlos prefers french fries.
Hope this helps! :3
Two sentences with por
La contacté por correo.
Te cambio mi manzana por tu sandwich.
Two sentences with para
¿Para dónde vas con tanta prisa?
No, Bruno. Estos chocolates no son para los perros.
Answer:
Mis padres estaban enojados. ESTABAN: imperfecto
Comía un sándwich. COMÍA: imperfecto
Tenían hambre. TENÍAN: imperfecto
Hope it helps :)
Explanation: