胡萝卜的新种子具有()特性。

题型:填空题

问题:

胡萝卜的新种子具有()特性。

考点:农艺师考试蔬菜栽培蔬菜栽培题库
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函数f(x)的定义域为A,若x1,x2∈A且f(x1)=f(x2)时总有x1=x2,则称f(x)为单函数。例如,函数f(x)=2x+1(x∈R)是单函数,下列命题:

①函数f(x)=x2(x∈R)是单函数;

②指数函数f(x)=2x(x∈R)是单函数;

③若f(x)为单函数,x1,x2∈A且x1≠x2,则f(x1)≠f(x2);

④在定义域上具有单调性的函数一定是单函数。

其中的真命题是(    )。(写出所有真命题的编号)

题型:填空题

阅读理解。

     Robert was born in a small town in England. His father has a farm and can supply him enough money to

finish university where he is studying law. The young man studies hard and hopes to be a famous lawyer.

     Last Monday their term was over. Robert said to his father on the telephone that he was going to travel in

a small country during his summer holiday. His father agreed to his plan and posted some money to him. So

he started four days ago. Their plane landed at the only airport of the country safely. He took a taxi and got to

a hotel in the center of the capital. He felt hungry and tired. So he had a dinner and then a good sleep. This

morning he was all right and was going to visit some places of interest. He met an English visitor while he was

having breakfast and the man told him to be careful of thieves.

     Robert thanked the man and left. But he thought he was smart and strong and he decided to have a try. He

brought a piece of paper and wrote on it, "A pig has stolen my wallet!" Then he put the note into his empty

wallet. After that he put the wallet into a pocket and set off. He did all carefully and hoped to find out who

would steal it.

     "Everything went well, "Robert thought to himself after he had returned to the hotel. He brought out his

wallet and put his money into it again. He had a look at the note. To his surprise, it was rewritten. It said,

"Your uncle has touched your wallet!"

1. Robert can study in the university because            . [ ]

A. he wants to be a lawyer

B. his father is a rich farmer

C. he's smart and strong

D. he keeps his wallet well

2. Robert went to the small country to            . [ ]

A. make fun of the thieves

B. catch some thieves

C. visit the places of interest

D. have a nice meal and a good sleep

3. The English visitor thought            . [ ]

A. there were a lot of thieves in the city

B. Robert could deal with the thieves

C. it was dangerous to travel in the city

D. Robert had to take good care of himself

题型:填空题

许多网络通信需要进行组播,以下选项中不采用组播协议的应用是()。在IPv4中把()类地址作为组播地址。

在IPv4中把()类地址作为组播地址。

A.A

B.B

C.D

D.E

题型:填空题

在我国,将图书馆划分为文化系统图书馆、教育系统图书馆、科学研究系统图书馆、工会系统图书馆等是按照那种标准划分的()

A、按图书馆的管理体制(隶属关系)划分

B、按馆藏文献范围划分

C、按用户群划分

D、按图书馆职能划分

题型:填空题

卸料时注意观察滤布和橡胶垫破损情况,滤布是否()等。及时更换破损滤布和滤板以保证滤液浓度。

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