Мы пролетали над горами, вершины ко

Мы пролетали над горами, вершины которых были покрыты снегом.

Results (English) 1:

We were flying over mountains, whose peaks are covered with snow.

Results (English) 2:

We flew over the mountains whose tops were covered with snow.

Results (English) 3:

we flew over the mountains, the peaks of which were covered with snow.