Johnny was three when he ran away from home for the first time.Somebody left the garden gate open.Johnny wandered out,crossed some fields,and two hours later , arrived in the next village .He was just able to give his name and address.

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Johnny was able to run away from home for the first time at the age of three because....

Because some person forgot to close the gate, and little johnny was able to run away from home.

because somebody left the garden gate open and Johny was very young to understand he could not did this.