About the spinal cord, which of the following descriptions are correct?（ ）
A.It occupies the whole vertebral canal. B.It presents the thoracic enlargement and lumbar enlargement. C.It has 30 segments: 7 cervical segments, 12 thoracic segments, 5 lumbar segments, 5 sacral segments, D.It is continuous with the brain stem. E.It terminates as conus medullaris (脊髓圆锥).正确答案DE
