"His daughters eat only pasta."
Translation:ילדותיו אוכלות אך ורק פסטה.
It intensifies the רק making it emphatic.
Wow this lesson is making me feel like I just started over with Hebrew. I am so lost
It's an emphatic only or exclusively: http://www.morfix.co.il/en/%D7%90%D7%9A%20%D7%95%D7%A8%D7%A7
Well, it's an idiom that should only be translated as a whole phrase and not word for word. Exclusively is probably the closest word in English but only would work too even if it's not quite strong enough (emphatic).
That actually helps though. Even if the literal translation doesn't make perfect sense, I understand the general idea of what it means. Thank you!