# teaching in their synagogues
"teaching in the synagogues of the Galileans" or "teaching in the synagogues of those people"
# preaching the gospel of the kingdom
"preaching the good news that God will show himself as king"
# every kind of disease and sickness
The words "disease" and "sickness" are closely related but should be translated as two different words if possible. "Disease" is what causes a person to be sick. "Sickness" is the physical weakness or affliction that results from having a disease.