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to stare (at); to gaze (at); to look hard (at); to watch intently; to fix one's eyes (on)
彼女は窓の外の景色をじっと見つめていた。
She was gazing intently at the scenery outside the window.
子供が水槽の中の魚を見つめて動かない。
The child is staring at the fish in the tank without moving.
彼は真剣な目で相手を見つめることができる。
He can look at the other person with serious eyes.