Sentence:  It is convenient to classify a child 's onset ages and completion ages as `` advanced '' , `` moderate '' ( modal ) , or `` delayed '' according to whether the child 's age equivalent `` dots '' appeared to the left of , upon , or to the right of the appropriate short <WSD>transverse</WSD> line . 
Meaning of the word marked with <WSD> tags:  extending or lying across; in a crosswise direction; at right angles to the long axis