Он молча уставился на НЛО.

The genders between the Russian and English text don’t match, if anything the English should say “He” instead of “She”

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310229 She stared at a UFO in silence.
498303 Он молча уставился на НЛО.
3110373 Κοιτούσε επίμονα στο ΟΥΦΟ χωρίς να μιλάει.

The Greek sentence also needs to be corrected.