Answer:
Mis padres (tienen)...
(Andar or andas ) dos kilometros...
Lo que (haces)....
Tu no (traes) nada a la fiesta
Nunca (sabes or saben ) la verdad
If it is singular by meaning: I, You , (Yo, tu) it's (sabes) but if it is plural meaning: they (ellos) it would be (saben )
Hope this helps :)