Heavens
Firmament, Sky, Skies
noun
The big thing in the sky is the heavens. The heavens where birds and planes soar, not the one you go to after you die if you've been really good.
The readings for this word are both kun'yomi readings. You've learned both of these readings by now so you should be able to read this on your own. Just remember that そら becomes ぞら because of rendaku here.
こんな日は、大空を見上げよう。
On a day like this, let's just look up at the sky.
ドローンが大空に広がっている。
Drones are spreading throughout the sky.
おじいちゃん、大空から私たちのこと見てくれているかな?
I wonder if Grandpa is watching us from the heavens?