(6分)为了探究环境温度对菜豆种子萌发的影响,小金同学设计了如下实验:①选用籽粒

题型:探究题

问题:

(6分)为了探究环境温度对菜豆种子萌发的影响,小金同学设计了如下实验:①选用籽粒饱满、均匀一致的菜豆种子60粒,将种子随机平均分成3组,分别放入三个垫有二层湿滤纸的培养皿内。②用记号笔在每个培养皿上做好标记(如图所示),然后将三个培养皿分别放到4℃、25℃、40℃的培养箱中恒温培养7天。③……。请回答下列问题:

(1)写出实验步骤③         

(2)除温度外,请再列举2个影响实验结果的其它变量         

(3)培养皿垫二层湿滤纸的目的是         

(4)若实验结果三个培养皿中都没找到发芽的菜豆,请分析可能的原因是       

(5)有同学说上述实验材料过于浪费,每个培养皿只需要放一粒菜豆种子就可以了。你是否同意这个说法并说明理由         

(6)小周同学用另一种植物种子做了上述实验,结果发现4℃环境中的种子萌发率明显高于其它二组。请推测该植物所生活的环境条件很可能是         

考点:种子萌发的条件和过程探究实验:种子萌发的环境条件探究实验:测定种子的发芽率
题型:探究题

T=2L/C为水锤的相长,阀门关闭时间为Ts,当满足()时发生间接水锤。

A、Ts<2L/C

B、Ts>2L/C

C、Ts=2L/C

题型:探究题

B
Here are two letters in WORKWORRIES, a column in a newspaper:
Dear Ariel,
I got a job offer from a high-tech company with a fairly satisfactory paycheck and benefits.Even the work environment is cool.But I heard that the job requires a lot of overtime and even weekends.I know it's important for newcomers to work hard to get their feet planted firmly on the ground, but I'm scared of the idea of having nearly no free time.I still need to find a girlfriend.So, shall I accept the job or give it up for another one with much less pay and more freedom?
Amoretto
Dear Amoretto,
I have two things to say: First, you're lucky to have such an excellent offer, especially at a time when so many qualified people are struggling to find any work at all; and second, you can't figure out your work-life balance until you're actually working.
Take the job.You'll be learning, doing interesting things, working in a cool environment, and making money.If you're given a contract (合同), make sure you understand the terms before you sign.Ask your boss how many hours a week you're expected to work.If they tell you a number that is much lower than what you find once you're working, you'll be in a better position to talk to them about it.
Give your work 100 percent.Work energetically and efficiently.If you're dedicated and focused, you might accomplish more than your co-workers in less time.Showing yourself to be a productive and talented worker for the beginning will give you more bargaining power.Finally, remember that taking a job doesn't have to be a life commitment.Try to give it at least a year (two is better).If you're really miserable after that time, look for another job that will give you more freedom.By then, you'll have workplace experience, bosses and colleagues who can speak positively about your work and some savings.Good luck!
Ariel
60.From Amoretto's letter, we know that he __________.
A.has been working for a long time      B.is likely a green hand
C.expects to change his job                D.is quite satisfied with the job
61.How can a man arrange his work-life balance according to Ariel?
A.By taking a training course.              B.By asking people for advice.
C.By comparing with others.              D.Through his own work experience
62.All of the following are advised byArial EXCEPT__________.
A.understanding the terms before signing
B.working hard and efficiently
C.getting a better position                    
D.doing the job at least a year
63.What does Ariel advise to do in the reply?
A.Take the job offered.                     B.Give up and find a new job.
C.Depend on your feeling.                  D.Choose jobs with great care
题型:探究题

关于子宫内膜异位症的描述,不正确的是()

A.一般见于生育年龄妇女,以25~45岁妇女多见

B.异位种植的子宫内膜随卵巢激素的变化而发生周期性出血

C.继发性痛经及渐进性加重为其典型症状

D.超声检查是目前国际公认的最佳诊断方法

E.具有增生、浸润、转移及复发等恶性行为

题型:探究题

过水准面上任何一点所作的铅垂线,在该点处与水准面正交。( )

题型:探究题

DSA能量减影常使用的两种管电压为()

A.50kV和110kV

B.60kV和120kV

C.70kV和130kV

D.80kV和140kV

E.90kV和150kV

更多题库