TOM SWIFT AND HIS WAR TANK (Annotated)

Ceasing his restless walk up and down the room, Tom Swift strode to the window and gazed across the field toward the many buildings, where machines were turning out the products evolved from the brains of his father and himself. There was a worried look on the face of the young inventor, and he seemed preoccupied, as though thinking of something far removed from whatever it was his eyes gazed upon."Well, I'll do it!" suddenly exclaimed Tom. "I don't want to, but I will. It's in the line of 'doing my bit, ' I suppose; but I'd rather it was something else. I wonder-""Ha! Up to your old tricks, I see, Tom!" exclaimed a voice, in which energy and friendliness mingled pleasingly. "Up to your old tricks!