【多选题】在连铸生产过程中,结晶器的功能是:
A.
高效率的传热器,把钢水热量迅速地传给冷却水;
B.
钢水凝固成型器,把钢水凝固成所规定的形状,如方坯、板坯、圆坯等;
C.
钢水净化器,使结晶器形成的坯壳所包含的液体钢水中的非金属夹杂物充分上浮被保护渣吸收,以进一步净化钢液;
【单选题】The silk trade negotiations have been __________ until May 4 to 6.
【单选题】患者,男性,70岁,慢性阻塞性肺气肿合并呼吸衰竭,在治疗过程中需定期做血气分析。护士在采集标本中错误的操作是( )
【判断题】市场环境包括市场结构,是一个比市场结构更为宽泛的概念。( )
【单选题】( )是决定旅游消费者购买力和支出的决定性因素
【单选题】About 79 million Americans have pre-diabetes(糖尿病前期). That means they have blood sugar thats higher than normal but not high enough to be diagnosed(诊断)with type 2—at least not yet. One long-term study ...
A.
Pre-diabetes will surely become type 2 diabetes.
B.
Pre-diabetes is likely to become diabetes within years.
C.
Enough attention should be paid to the treatment of type 2.
D.
Pre-diabetes is ranked No. 1 danger threatening Americans' health.
【判断题】市场环境包括市场结构,是一个比市场结构更为宽泛的概念。