“在.学习” 用介词in 即：study in a school / study in a middle school
at school 表示“某人在学校”
如：Where is she ----- She is at school 她在哪里?她在学校.�����Ҫ����һ����ѧѧϰ������˼�ǻ�Ҳ���á�study in a middle school������ã����� �磺 She is a girl and she studies in No.2 middle school.�� ����һ��Ů�� ���ڵڶ���ѧ���飨��ѧ����ϣ������а������ʿɲ�����˵��I study in a middle school������ã� ���Եġ�