I soon found that the work I was doing had already been done by someone else.________，I was wasting my time.

A．In other words           B．In a word              C．First of all           D．Believe it or not

I soon found that the work I was doing had already been done by someone else. _______, I was wasting my time.

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I soon found that the work I was doing had already been done by someone else - ________, I was wasting my time.