How to pronounce 光是 in Cantonese (3 out of 4):

光是拿來吃,不夠 eating them is not quite enough
Just eating them is not quite enough.

Cantonese Sentence Breakdown

光是 gwong1 si6
merely
拿來 naa4 loi4
bring over
hek3
to eat
to consume
to eat at (a cafeteria etc)
to eradicate
to destroy
to absorb
to suffer
不夠 bat1 gau3
not enough