我国大气污染物排放标准中,烟囱的有效高度指()
A.烟气抬升高度;
B.烟气抬升高度和烟囱几何高度之和;
C.烟囱几何高度
D.烟囱几何高度和烟气抬升高度之差。
参考答案:B
Prevention of preterm births is vital for which of the following reasons
A.It's costly to care for these neonates.
B.These neonates are usually mentally retarded.
C.Preterm birth causes high incidence of the neonatal deaths.
D.These neonates usually wind up with long-term health care needs.
医学模式是:()
A.某一时代各种医学思想的集中反映
B.某一时代各种医学学派的集中反映
C.对医学各门类的总称
D.对医学知识和技术的总称