答案：D

题目分析：在so……that句型中，当把so前置时，主句需用部分倒装的形式。本句的正常语序是：The distance is so great that many parents are too worried to let their children travel alone at the beginning of the new term.句意：距离太远许多父母太担心不让他们的孩子在新学期初独自旅行。