Well, GospelExplainned, I'm sure there are more qualified people to answer this, but none of them are taking pity on you, so I'll give it a whirl. I have studied both languages and am fairly fluent in Biblical Greek, so maybe I'm qualified. :smilewinkgrin:
First of all, Hebrew was a dead language for hundreds of years. Nobody could speak it but a few Jewish scholars. Then in the late 19th century, Zionists began to plan to have a Jewish homeland once again. For that, they knew they would need a national language, since Jews live all over the world. They resurrected Hebrew, and began to teach it to Jews all over the world in preparation for that homeland, and that is why we have modern Hebrew now!
As for how it differs from ancient Hebrew, not as much as you might think because of how it was resurrected from ancient Hebrew. The main difference, as I understand it, is that modern Hebrew has had to add many new words for technological terms, etc.
Greek is a different story. It has been continually in existence for several thousand years, so it has changed quite a bit since the first century. The primary difference is in the verb forms, as I understand it. Modern Greek is less complicated in this area than ancient Greek. However, many of the vocabulary words are very close to that of ancient Greek, so I can read some modern Greek.
I hope this helps! :wavey: