【单选题】男,54岁。为成人牙周炎患者,牙周基础治疗后6周复查时,多数牙牙颈部有菌斑,但无牙石,牙龈边缘仍有轻度充血、水肿,影响其疗效的主要因素是
【单选题】In 17th-century New England, almost everyone believed in witches. Struggling to survive in a vast and sometimes unforgiving land, America's earliest European settlers understood themselves to be surro...