Sentence:  The length of the arrow indicates amount of slowing or acceleration at Completion over that at Onset , and the difference in months can be <WSD>read</WSD> roughly by referring the arrow to the age scale along the base of each figure , or more precisely by referring to the original data in the appropriate tables . 
Meaning of the word marked with <WSD> tags:  interpret something in a certain way; convey a particular meaning or impression