A handful of nouns appear to be plural in form but take a singular verb: 1  The news is bad. 2  Gymnastics is fun to watch.  Economics/mathematics/statistics is said to be difficult. (Economics can sometimes be a plural concept, as in The economics of the situation demand that . . . .)
Early childhood: This stage ranges from 18 months to 3 years. By second year of life, the muscular and nervous systems have developed markedly, and the child is eager to acquire new skills, is no longer content to sit and watch.
Child development stages. Child development stages are the theoretical milestones of child development, some of which are asserted in nativist theories. This article discusses the most widely accepted developmental stages.