皮皮学，免费搜题
登录
搜题
【单选题】
下列几种盐溶液浓度相同，其pH值最小的是：
A.
KCl
B.
Na2S
C.
Na2CO3
D.
NaH2PO4
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
.
..
皮皮学刷刷变学霸
举一反三
【单选题】一个质量为 M 的箱子放在水平地面上,箱内用一段固定长度的轻质细线拴一质量为 m 的小球,线的另一端拴在箱子的顶板上,现把细线和球拉到左侧与竖直方向成 θ 角处从静止释放,如图所示, 在小球摆动过程中箱子始终保持静止。以下判断正确的( )
A.
在小球摆动的过程中，线的张力呈周期性变化，但箱子对地面的作用力始终保持不变
B.
小球摆到右侧最高点时，地面受到的压力为 (M+m)g ，箱子受到地面向左的摩擦力
C.
小球摆到最低点时，地面受到的压力为 (M+m)g ，箱子不受地面的摩擦力
D.
小球摆到最低点时，绳对箱顶的拉力大于 mg ，箱子对地面的压力大于 (M+m)g
查看完整题目与答案
【单选题】在Excel函数中SUM(B1:B4)等价于（ ）。
A.
SUM(A1:B4 B1:C4)
B.
SUM(B1+B4)
C.
SUM(B1+B2 B3+B4)
D.
SUM(B1，B2， B3，B4)
查看完整题目与答案
【简答题】设计洪水的标准按保护对象的不同分为两类：第一类为保障 的防洪标准；第二类为确保水库大坝等水工建筑物自身安全的洪水标准。
查看完整题目与答案
【多选题】工程经济分析的可比性原则主要有( )
A.
价格指标可比性
B.
时间的可比性
C.
满足需要的可比性
D.
消耗费用的可比性
E.
效益可比性
查看完整题目与答案
【多选题】工程经济分析的可比性原则主要有( )
A.
价格指标可比性
B.
满足需要的可比性
C.
时间可比性
D.
消耗费用的可比性
E.
效益可比性
查看完整题目与答案
【简答题】Given the chance to show his ability, he regained ______________ and began to succeed in school.
查看完整题目与答案
【简答题】如图，在边长为4的正方形ABCD中，动点E以每秒1个单位长度的速度从点A开始沿边AB向点B运动，动点F以每秒2个单位长度的速度从点B开始沿折线BC﹣CD向点D运动，动点E比动点F先出发1秒，其中一个动点到达终点时，另一个动点也随之停止运动，设点F的运动时间为t秒． （1）点F在边BC上． ①如图1，连接DE，AF，若DE⊥AF，求t的值； ②如图2，连结EF，DF，当t为何值时，△EBF与△DCF...
查看完整题目与答案
【单选题】下列句子,“而”的用法与“蟹六跪而二螯”的“而”相同的一-组是( ) 1积善成德,而神明自得 2锲而不舍,朽木不折 3先帝创业未半而中道崩殂 4此臣所以报先帝而忠陛下之职分也 5黑质而白章 6吾恂恂而起 7得之心而寓之酒也
A.
①③⑤
B.
②④⑦
C.
④⑤⑦
D.
③⑥⑦
查看完整题目与答案
【多选题】Part I Words in use ( 10 points , 1 points for each) Directions : Fill the blanks by selecting suitable words from the word blank.Each word is marked with a letter. Answer the questions by marking the...
A.
estimate
B.
donation
C.
transform
D.
resources
E.
subsequent
F.
circumstances
G.
intense
H.
embarrassed
I.
advocate
J.
confidence 1. Given the chance to show his ability, he regained and began to succeed in school. 2. People are beginning to realize that to nature at will is the biggest mistake that man has ever made. 3. It was difficult to how many people had been wounded in the earthquake 4. As music plays an important role in our life, many music teachers and educators taking up a musical instrument at a young age. 5. I got from him only a letter, which was put on my office desk; to the receipt of this letter I have never heard from him. 6. John believes that the of food to the hungry is more helpful than giving money. 7. He was when he discovered that he didn't have enough money to pay for the red wine he had ordered. 8. It is well known that China is a country with rich natural and a very big population. 9. They kept on trying their best to develop their business, but in suc h market competition, they had no idea if success would come along one day. 10. This rule should be entirely clear in the min ds of everyone and should not be misunderstood under any .
查看完整题目与答案
【简答题】在气动弹性设计准则中,所用机翼剖面示意图如下,请写出2点的名称。
查看完整题目与答案
相关题目：
【单选题】一个质量为 M 的箱子放在水平地面上,箱内用一段固定长度的轻质细线拴一质量为 m 的小球,线的另一端拴在箱子的顶板上,现把细线和球拉到左侧与竖直方向成 θ 角处从静止释放,如图所示, 在小球摆动过程中箱子始终保持静止。以下判断正确的( )
A.
在小球摆动的过程中，线的张力呈周期性变化，但箱子对地面的作用力始终保持不变
B.
小球摆到右侧最高点时，地面受到的压力为 (M+m)g ，箱子受到地面向左的摩擦力
C.
小球摆到最低点时，地面受到的压力为 (M+m)g ，箱子不受地面的摩擦力
D.
小球摆到最低点时，绳对箱顶的拉力大于 mg ，箱子对地面的压力大于 (M+m)g
查看完整题目与答案
【单选题】在Excel函数中SUM(B1:B4)等价于（ ）。
A.
SUM(A1:B4 B1:C4)
B.
SUM(B1+B4)
C.
SUM(B1+B2 B3+B4)
D.
SUM(B1，B2， B3，B4)
查看完整题目与答案
【简答题】设计洪水的标准按保护对象的不同分为两类：第一类为保障 的防洪标准；第二类为确保水库大坝等水工建筑物自身安全的洪水标准。
查看完整题目与答案
【多选题】工程经济分析的可比性原则主要有( )
A.
价格指标可比性
B.
时间的可比性
C.
满足需要的可比性
D.
消耗费用的可比性
E.
效益可比性
查看完整题目与答案
【多选题】工程经济分析的可比性原则主要有( )
A.
价格指标可比性
B.
满足需要的可比性
C.
时间可比性
D.
消耗费用的可比性
E.
效益可比性
查看完整题目与答案
【简答题】Given the chance to show his ability, he regained ______________ and began to succeed in school.
查看完整题目与答案
【简答题】如图，在边长为4的正方形ABCD中，动点E以每秒1个单位长度的速度从点A开始沿边AB向点B运动，动点F以每秒2个单位长度的速度从点B开始沿折线BC﹣CD向点D运动，动点E比动点F先出发1秒，其中一个动点到达终点时，另一个动点也随之停止运动，设点F的运动时间为t秒． （1）点F在边BC上． ①如图1，连接DE，AF，若DE⊥AF，求t的值； ②如图2，连结EF，DF，当t为何值时，△EBF与△DCF...
查看完整题目与答案
【单选题】下列句子,“而”的用法与“蟹六跪而二螯”的“而”相同的一-组是( ) 1积善成德,而神明自得 2锲而不舍,朽木不折 3先帝创业未半而中道崩殂 4此臣所以报先帝而忠陛下之职分也 5黑质而白章 6吾恂恂而起 7得之心而寓之酒也
A.
①③⑤
B.
②④⑦
C.
④⑤⑦
D.
③⑥⑦
查看完整题目与答案
【多选题】Part I Words in use ( 10 points , 1 points for each) Directions : Fill the blanks by selecting suitable words from the word blank.Each word is marked with a letter. Answer the questions by marking the...
A.
estimate
B.
donation
C.
transform
D.
resources
E.
subsequent
F.
circumstances
G.
intense
H.
embarrassed
I.
advocate
J.
confidence 1. Given the chance to show his ability, he regained and began to succeed in school. 2. People are beginning to realize that to nature at will is the biggest mistake that man has ever made. 3. It was difficult to how many people had been wounded in the earthquake 4. As music plays an important role in our life, many music teachers and educators taking up a musical instrument at a young age. 5. I got from him only a letter, which was put on my office desk; to the receipt of this letter I have never heard from him. 6. John believes that the of food to the hungry is more helpful than giving money. 7. He was when he discovered that he didn't have enough money to pay for the red wine he had ordered. 8. It is well known that China is a country with rich natural and a very big population. 9. They kept on trying their best to develop their business, but in suc h market competition, they had no idea if success would come along one day. 10. This rule should be entirely clear in the min ds of everyone and should not be misunderstood under any .
查看完整题目与答案
【简答题】在气动弹性设计准则中,所用机翼剖面示意图如下,请写出2点的名称。
查看完整题目与答案