Sentence:  Although the primary mathematical properties of the middle number at the center of the Lo Shu , and the interrelation of all the other numbers to it , might seem enough to <WSD>account</WSD> for the deep fascination which the Lo Shu held for the Old Chinese philosophers , this was actually only a beginning of wonders . 
Meaning of the word marked with <WSD> tags:  be the reason or explanation for