哪里那么容易缺钙了。。。 According to the Denver II Developmental Assessment milestone's chart, infants usually: * stand, holding on to things between 6 1/2 to 8 1/2 months * pull to a standing position between 8 to 10 months * stand for about 2 seconds between 9 to 11 1/2 months * stand alone between 11 to 13 1/2 months The other big question parents often have concerns the safety of allowing younger infants to stand up with support and bear weight on their legs. Most younger infants are ab