1. The hope of high profits lured him into questionable dealings. �������ϣ����ʹ��������������Ľ��ס�
2. Does the writer use questionable assumptions without addressing problems which might be inherent in those assumptions? �����Ƿ�������������裬��δ������ܰ�������Щ�����е����⣿
3. The merits of competition by examination are somewhat questionable, but competition in the certain knowledge of failure is positively harmful. ���Եľ�����ֵ��Щֵ�û��ɣ�������ȷ��֪����ʧ�ܵľ���ȴ�ǿ϶��к��ġ�