Children develop at their own pace, so it's impossible to tell exactly when yours will learn a given skill. The developmental milestones below will give you a general idea of the changes you can expect as your child gets older, but don't be alarmed if your child takes a slightly different course.

Social

* Imitates adults and playmates
* Spontaneously shows affection for familiar playmates
* Can take turns in games
* Understands concept of "mine" and "his/hers"

Emotional

* Expresses affection openly
* Expresses a wide range of emotions
* By 3, separates easily from parents
* Objects to major changes in routine

Cognitive

* Makes mechanical toys work
* Matches an object in her hand or room to a picture in a book
* Plays make-believe with dolls, animals, and people
* Sorts objects by shape and color
* Completes puzzles with three or four pieces
* Understands concept of "two"

Language

* Follows a two- or three-part command
* Recognizes and identifies almost all common objects and pictures
* Understands most sentences
* Understands placement in space ("on," "in," "under")
* Uses 4- to 5-word sentences
* Can say name, age, and sex
* Uses pronouns (I, you, me, we, they) and some plurals (cars, dogs, cats)
* Strangers can understand most of her words

Movement

* Climbs well
* Walks up and down stairs, alternating feet (one foot per stair step)
* Kicks ball
* Runs easily
* Pedals tricycle
* Bends over easily without falling

Hand and Finger Skills

* Makes up-and-down, side-to-side, and circular lines with pencil or crayon
* Turns book pages one at a time
* Builds a tower of more than six blocks
* Holds a pencil in writing position
* Screws and unscrews jar lids, nuts, and bolts
* Turns rotating handles

Developmental Health Watch
Alert your child's doctor or nurse if your child displays any of the following signs of possible developmental delay for this age range.

* Frequent falling and difficulty with stairs
* Persistent drooling or very unclear speech
* Cannot build a tower of more than four blocks
* Difficulty manipulating small objects
* Cannot copy a circle by age 3
* Cannot communicate in short phrases
* No involvement in "pretend" play
* Does not understand simple instructions
* Little interest in other children
* Extreme difficulty separating from mother or primary caregiver
* Poor eye contact
* Limited interest in toys
* Experiences a dramatic loss of skills he or she once

From CARING FOR YOUR BABY AND YOUNG CHILD: BIRTH TO AGE 5 by Steven Shelov, Robert E. Hannermann, © 1991, 1993, 1998, 2004 by the American Academy of Pediatrics. Used by permission of Bantam Books, a division of Random House, Inc.