When will the 70 years end?
Radak: Nebuchadnetzar ruled for 45 years. What is the source? His son Evil Merudach ruled in the 37th year from the exile of Melech Yehoyachin, like it says in Melachim II, 2:25 and below (52:31), and Yehoyachin was exiled in the eighth year of Nebuchadnetzar. This shows that Nebuchadnetzar ruled for 45 years. His son Evil Merudach ruled for 23 years. What is the source? We find that his son Belshatzar ruled for three years. This leaves 23 in between. Belshatzar did not complete three years, for he was killed in his third year. In all, there are 70 - 45, 23 and two.
Who is "ha'Goy ha'Hu"?
Malbim: It is the nation of Bavel, the capitol city.
What is their sin?
Malbim: They destroyed lands.
What is the grammatical form of "Shimemos"?
Radak: It is derived from Shemamah. It is Samuch [to Olam].