1)
What causes the land to be desolate?
1.
Radak: Their evil ways cause this.
2)
Why do they whistle?
1.
Rashi: One who passes by ruins, and he saw when they are nice buildings, it is normal for him to whistle.
3)
Why does it say "Sherikos Olam"?
1.
Radak: Everyone who passes will whistle. This will be forever, i.e. for a long time.
2.
Malbim: The desolation will be permanent, i.e. for a long time.
4)
What is the meaning of "Yisom"?
1.
Rashi: He will be astounded.
5)
Why will he shake his head?
1.
Radak: One who is astounded does so.