Stroke means touch lightly and repeatedly, as with brushing motions
"He stroked his long beard"
strike means
1.Deliver a sharp blow, as with the hand, fist, or weapon
"The teacher struck the child"; "the opponent refused to strike"; "The boxer struck the attacker dead"
2.Hit against; come into sudden contact with
"He struck the table with his elbow"
3.Make a strategic, offensive, assault against an enemy, opponent, or a target
"The Germans struck Poland on Sept. 1, 1939"; "We must strike the enemy's oil fields"; "in the fifth inning, the Giants struck, sending three runners home to win the game 5 to 2"
Beat means
1.Come out better in a competition, race, or conflict
"Agassi beat Becker in the tennis championship"; "We beat the competition"
2.Give a beating to; subject to a beating, either as a punishment or as an act of aggression
"Thugs beat him up when he walked down the street late at night"; "The teacher used to beat the students"
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