按照《五金交电家电化工商品的购销合同实施办法》规定，供方错发到站、中转单位、收货单位

若m,n互为相反数，则5m+5n－5=________

⑴在25℃条件下将pH=11的氨水稀释100倍后溶液的pH为（填序号）__       __。

A．9          B．13         C．11～13之间          D．9～11之间

⑵25℃时，向0.1mol/L的氨水中加入少量氯化铵固体，当固体溶解后，测得溶液pH减小，主要原因是（填序号）__               ___。

A．氨水与氯化铵发生化学反应

B．氯化铵溶液水解显酸性，增加了c(H⁺)

C．氯化铵溶于水，电离出大量铵离子，抑制了氨水的电离，使c(OH^―)减小

⑶已知某溶液中只存在OH^－、H⁺、NH₄⁺、Cl^－四种离子，某同学推测该溶液中各离子浓度大小顺序可能有如下四种关系：

A．c(Cl^－)＞c(NH₄⁺)＞c(H⁺)＞c(OH^－)    B．c(Cl^－)＞c(NH₄⁺)＞c(OH^－)＞c(H⁺)

C．c(Cl^－)＞c(H⁺)＞c(NH₄⁺)＞c(OH^－)    D．c(NH₄⁺)＞c(Cl^－)＞c(OH^－)＞c(H⁺)

①若溶液中只溶解了一种溶质，该溶质是         ，上述离子浓度大小顺序关系中正确的是（选填序号）                        。

②若上述关系中C是正确的，则溶液中溶质是                          。

在实验室中用达西实验装置来测定土样的渗流系数，见图6-50。圆筒直径为20cm，土层厚度为40cm（即两测压管间距为40cm）。测得通过流量Q为100ml/min，两测压管的水头差为20cm，则计算土样的渗透系数为（）。

A.0.0214cm/s

B.0.0376cm/s

C.0.0592cm/s

D.0.0106cm/s

Stress is our response to threatening or (1) events. We may experience different levels of stress depending on the (2) , meaning the events or circumstances that cause us to feel stress. Stressors can be classified into (3) main categories: (4) events, personal stressors, and (5) stressors. Cataclysmic events are major events that cause stress (6) , immediately, for a great many people at once. Personal stressors are major life events that create stress, including (7) life events. Background stressors are (8) hassles, or minor irritations, or (9) background stressors. Repeated exposure to stressors has both psychological and (10) consequences. The long- term consequence is that body tissues such as the heart and blood vessels can begin to (11) . The (12) system functions less effectively, and (13) our ability to fight off illnesses.
The General Adaptation (14) explains the sequence of physiological reactions to stress. There are three phases to G. A. S. The first is the " alarm and (15) " phase: we respond with alarm, and take (16) to remove the stressor. The second phase is the (17) stage: we fight against the stressor or try to cope with the stressor. This can lead to the third phase. (18) . The exhaustion phase may be an (19) way of trying to avoid the stressors. The body may be telling us that we need to do whatever is (20) to remove the stressor.

Stress is our response to threatening or (1) events. We may experience different levels of stress depending on the (2) , meaning the events or circumstances that cause us to feel stress. Stressors can be classified into (3) main categories: (4) events, personal stressors, and (5) stressors. Cataclysmic events are major events that cause stress (6) , immediately, for a great many people at once. Personal stressors are major life events that create stress, including (7) life events. Background stressors are (8) hassles, or minor irritations, or (9) background stressors. Repeated exposure to stressors has both psychological and (10) consequences. The long- term consequence is that body tissues such as the heart and blood vessels can begin to (11) . The (12) system functions less effectively, and (13) our ability to fight off illnesses.
The General Adaptation (14) explains the sequence of physiological reactions to stress. There are three phases to G. A. S. The first is the " alarm and (15) " phase: we respond with alarm, and take (16) to remove the stressor. The second phase is the (17) stage: we fight against the stressor or try to cope with the stressor. This can lead to the third phase. (18) . The exhaustion phase may be an (19) way of trying to avoid the stressors. The body may be telling us that we need to do whatever is (20) to remove the stressor.

（）都可能会引起抽采用瓦斯泵的抽采困难。

A.较长时间停机

B.填料太干

C.启动水位过高

D.皮带太紧