引起牙周脓肿最常见的病原菌是
A．甲型溶血性链球菌B．类白喉杆菌C．无芽胞厌氧菌D．铜绿假单胞菌E．白念珠菌(白假丝酵母菌)
参考答案：C
________ she couldn’t understand was ________ fewer and fewer students showed interest in her lessons.
A．What；why
B．That；what
C．What；because
D．Why；that
学龄期患儿进行沟通要注意什么？
