can tell the difference
注意深く観察すれば違いがわかるでしょう。
If you look closely, you'll notice the difference.
その違いがわかるでしょう。
You'll be able to tell the difference.
"違いがわかるはず"
You should be able to tell the difference.
— バジュランギおじさんと、小さな迷子 (2015)
違いがわかるかい？
Can you tell the difference?
君にその違いがわかるくらいの頭があってほしいなあ。
I wish you were smart enough to understand the difference.