The child suffered severe mental retardation.这个孩子患有严重的智力迟钝。The mental retardation is evident.智力迟钝是一目了然的。Severe iron deficiency can cause developmental delay and growth retardation.严重缺铁会导致发育迟缓。The chemical induced a retardation of cell growth.这种化学品抑制细胞生长。