1)
When did he give to Yerushalayim to drink?
1.
Radak: He gave to Yerushalayim first 1 , for these nations were stricken via Nebuchadnetzar, and in his first year of kingship, the fourth year of Yehoyakim, he came against Yerushalayim.
1
Malbim: Yerushalayim was destroyed before Egypt. (Even though verse 17 said that he gave to Kol ha'Goyim to drink, this is a Klal; Yisrael and Yerushalayim are included. Our verse begins a list of who drank, and Yerushalayim is first. - PF)
2)
Who are its kings?
1.
Radak: Yehoyakim, Yehoyachin and Tzidkiyah.
3)
What is "ka'Yom ha'Zeh"?
1.
Rashi: Like they are today, after the Churban, when Yirmeyah wrote his Sefer.