皮皮学，免费搜题
登录
搜题
【单选题】
能说明 BF 3 分子的 4 个原子在同一平面的理由是
A.
． B—F 键的键角为 120°
B.
． B—F 键是非极性键
C.
． 3 个 B—F 键的键能相等
D.
． 3 个 B—F 键的键长相等
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
【简答题】9 A.Driving a car. B.Riding a bike. C.Walking around. D.Jogging and exercising.
查看完整题目与答案
【单选题】利用另一种液体在运动过程中的能量变化来输送液体称为其它类型泵，属于这种类型的泵是（）。
A.
喷射泵
B.
螺杆泵
C.
计量泵
D.
离心泵
查看完整题目与答案
【简答题】听短文，回答问题。 1. It was about _______ when I saw the car accident. [     ] A. 11 am B. 11 pm C. 9 am 2. The woman was _______ after the car hit the wall of the building. [     ] A. not hurt B. badly hurt ...
查看完整题目与答案
【简答题】根据图画和短文中首字母提示完成单词。 Mrs. Brown i _____ (1) driving a car. Mr. Brown is s_____ (2) on the back s_____ (3). Mrs. Brown stops the car, b_____ (4) Mr. Brown says, 'You mustn't park here. Because the sign (...
查看完整题目与答案
【单选题】听力原文：M: I need to send in an accident report. Tell me in your own words Mrs. Nanthy. W: Well, I was driving along Jefferson Street, between 19th and 20th Street. I wasn't going fast at all. I saw a ca...
A.
Between 19th and 20th Jefferson Street.
B.
Between 19th and 20th Jackson Street.
C.
Between 9th and 10th Jackson Street.
D.
Between 90th and 91th Jefferson Street.
查看完整题目与答案
【多选题】Perhaps, language should be looked upon as a ___1______ and a ________2___________: often study the road map (check grammar) and ____3____ the car engine (adjust vocabulary). Learning grammar and a go...
A.
road map
B.
valuable possession
C.
tune up
D.
well-conditioned
E.
Precise
F.
effective
G.
beneficial
H.
essential
I.
not being taught
查看完整题目与答案
【判断题】[判断题]在圆杆上套丝时,要始终加以压力,连续不断的 旋转,这样套出的螺纹精度高。
A.
正确
B.
错误
查看完整题目与答案
【判断题】单级离心泵由动部件叶轮和泵轴、静部件泵壳填料函和轴承两大部分组成。叶轮是关键部件，通常由若干片后弯叶片组成，结构有闭式、半开式和开式三种。开式叶轮可输送含颗粒悬浮液，但易倒流，效率较低。叶轮吸液有单吸和双吸式两种。一般的流程是液体通过底阀，由吸入管路进入离心泵，经叶轮提供能量，再经蜗道(volute)、压出管路排出。吸入管路可以设调节阀以控制流量，且管径可以大于排出管的管径。多级离心泵的泵轴上接有...
A.
正确
B.
错误
查看完整题目与答案
【单选题】Why does the woman become a taxi driver?
A.
She owns a car.
B.
She drives well.
C.
She loves driving.
D.
She wants to dress neatly.
查看完整题目与答案
【单选题】离心泵的气缚现象是指?
A.
用离心泵输送气体时不能获得很高的扬程
B.
离心泵出口管路中没有安装旁路导致突然停泵时叶轮被出口管中返回的水冲坏
C.
因离心泵安装位置过低,不能正常运转
D.
因离心泵内有气体失去了输送液体的能力
查看完整题目与答案
相关题目：
【简答题】9 A.Driving a car. B.Riding a bike. C.Walking around. D.Jogging and exercising.
查看完整题目与答案
【单选题】利用另一种液体在运动过程中的能量变化来输送液体称为其它类型泵，属于这种类型的泵是（）。
A.
喷射泵
B.
螺杆泵
C.
计量泵
D.
离心泵
查看完整题目与答案
【简答题】听短文，回答问题。 1. It was about _______ when I saw the car accident. [     ] A. 11 am B. 11 pm C. 9 am 2. The woman was _______ after the car hit the wall of the building. [     ] A. not hurt B. badly hurt ...
查看完整题目与答案
【简答题】根据图画和短文中首字母提示完成单词。 Mrs. Brown i _____ (1) driving a car. Mr. Brown is s_____ (2) on the back s_____ (3). Mrs. Brown stops the car, b_____ (4) Mr. Brown says, 'You mustn't park here. Because the sign (...
查看完整题目与答案
【单选题】听力原文：M: I need to send in an accident report. Tell me in your own words Mrs. Nanthy. W: Well, I was driving along Jefferson Street, between 19th and 20th Street. I wasn't going fast at all. I saw a ca...
A.
Between 19th and 20th Jefferson Street.
B.
Between 19th and 20th Jackson Street.
C.
Between 9th and 10th Jackson Street.
D.
Between 90th and 91th Jefferson Street.
查看完整题目与答案
【多选题】Perhaps, language should be looked upon as a ___1______ and a ________2___________: often study the road map (check grammar) and ____3____ the car engine (adjust vocabulary). Learning grammar and a go...
A.
road map
B.
valuable possession
C.
tune up
D.
well-conditioned
E.
Precise
F.
effective
G.
beneficial
H.
essential
I.
not being taught
查看完整题目与答案
【判断题】[判断题]在圆杆上套丝时,要始终加以压力,连续不断的 旋转,这样套出的螺纹精度高。
A.
正确
B.
错误
查看完整题目与答案
【判断题】单级离心泵由动部件叶轮和泵轴、静部件泵壳填料函和轴承两大部分组成。叶轮是关键部件，通常由若干片后弯叶片组成，结构有闭式、半开式和开式三种。开式叶轮可输送含颗粒悬浮液，但易倒流，效率较低。叶轮吸液有单吸和双吸式两种。一般的流程是液体通过底阀，由吸入管路进入离心泵，经叶轮提供能量，再经蜗道(volute)、压出管路排出。吸入管路可以设调节阀以控制流量，且管径可以大于排出管的管径。多级离心泵的泵轴上接有...
A.
正确
B.
错误
查看完整题目与答案
【单选题】Why does the woman become a taxi driver?
A.
She owns a car.
B.
She drives well.
C.
She loves driving.
D.
She wants to dress neatly.
查看完整题目与答案
【单选题】离心泵的气缚现象是指?
A.
用离心泵输送气体时不能获得很高的扬程
B.
离心泵出口管路中没有安装旁路导致突然停泵时叶轮被出口管中返回的水冲坏
C.
因离心泵安装位置过低,不能正常运转
D.
因离心泵内有气体失去了输送液体的能力
查看完整题目与答案