【多选题】关于“载流子的扩散运动”,以下说法正确的是:
B.
均匀掺杂的半导体,处于热平衡状态时,不产生扩散运动
C.
不论是平衡载流子还是非平衡载流子,只要存在浓度梯度,都会产生扩散运动
【单选题】Which of the following does the woman want to know?
A.
If a product is in stock
B.
If a discount is possible
C.
If an order can be cancelled
D.
If a purchase can be returned
【单选题】How does the total production cost change if the unit product cost in the current period is 6% lower than that in the base period and the output increases by 6%?
【单选题】锅炉一次蒸汽系统上所装的全部安全阀排汽量的总和,必须 ( ) 锅炉最大连续蒸发量。 ; ; 。
【单选题】If the product does absorb moisture or ________ water, discard it.
B.
becomes saturated with
【简答题】______select pupils on grounds of their ability in the test and are usually single ed schools i.e. children either go to boys school or girls school.
【单选题】男性,65岁。确诊慢性支气管炎、肺气肿5年,此次再次发作,呼吸困难加重且伴有发绀入院,未吸氧。下列血气结果与之相符的是