教学的科学性是指教学内容要正确地反映客观世界及其运动规律，教给学生科学知识。( )

A new study found ______ a teacher has anxiety about math, ______ feeling can influence how his or her female students feel about math.

A．when that; which

B．that when; that

C．that if; which

D．if that; that

患者，女，28岁。已婚。妊娠后 * * 少量出血，伴小腹隐痛，腰酸，恶心纳差，舌苔白。脉细滑。B超检查示宫内可见胎囊。应首先考虑的是( )

A．难免流产
B．先兆流产
C．习惯性流产
D．稽留流产
E．不全流产

代表社区牙周指数的是（）

A.CPI

B.CPrTN

C.CPD

D.OHI

E.DI

气送上料管断裂预防措施及处置。