为分离色度信号的U与V两个分量,延时解调电路中应有直通信号和延时信号两个信号。

题型:判断题

问题:

为分离色度信号的U与V两个分量,延时解调电路中应有直通信号和延时信号两个信号。

考点:信息安全知识竞赛临床诊疗伦理与临终关怀与死亡的伦理临床诊疗伦理与临终关怀与死亡的伦理题库
题型:判断题

(11分)某同学在研究灯泡的电阻随灯泡两端电压增大而变化的实验中,用伏安法分别测出A、B两个灯泡的伏安特性曲线如图所示。

(1)若用多用表欧姆档测B灯的电阻,其阻值约为________Ω。

(2)若将A灯接在由8节电动势均为2V,内阻均为0.5Ω的电池串联而成的电源两端,A灯的实际功率为________W。

(3)若将A灯和B灯并联接在上述电源两端,B灯的实际功率为________W。

题型:判断题

An Invisible Smile

Mr. Dawson was an old grouch, and everyone in town knew it. Kids knew not to go into his yard to pick a delicious apple. Old Dawson, they said, would come after you with his gun.

One Friday, 12-year-old Janet was going to stay all night with her friend Amy. They had to walk by Dawson's house on the way to Amy's house, but as they got close, Janet saw him sitting on his front porch and suggested they cross over to the other side of the street. Like most of the children, Janet was scared of the old man.

Amy said not to worry. Mr. Dawson wouldn't hurt anyone. Still, Janet was growing more nervous with each step closer to the old man's house. When they got close enough, Dawson looked up with his usual frown (皱眉), but when he saw it was Amy, a broad smile changed his entire face as he said, "Hello Miss Amy. I see you've got a little friend with you today."

Amy smiled back and told him Janet was staying overnight and they were going to listen to music and play games. Mr. Dawson said that sounded fun, and offered them each a fresh picked apple off his tree. They gladly accepted. Mr. Dawson had the best apples in the whole town.

When they left, Janet asked Amy, "Everyone says he's the meanest man in town. How come he was so nice to us?"

Amy explained that when she first started walking past his house he wasn't very friendly and she was afraid of him, but she pretended he was wearing an invisible smile and so she always smiled back at him. It took a while, but one day he half-smiled back at her.

After some more time, he started smiling real smiles and then started talking to her. Just a "hello" at first, then more. She said he always offers her an apple now, and is always very kind.

"An invisible smile?" questioned Janet.

"Yes," answered Amy, "my grandma told me that if I pretended I wasn't afraid and pretended he was smiling an invisible smile at me and I smiled back at him, sooner or later he would really smile. Grandma says smiles are contagious."

If we remember what Amy's grandma said, that everyone wears an invisible smile, we too will find that We're always on the go trying to accomplish so much, aren't we? It's so easy to get caught up in everyday life that we forget how simple it can be to bring cheer to ourselves and others. Giving a smile away takes so little effort and time, let's make sure that we're not the one that others have to pretend to be wearing an invisible smile.

小题1:Kids were scared of Mr. Dawson because _____.

A.he was wearing an invisible smile

B.he would fire them with a gun

C.he was mean with his apples

D.he was always very cold小题2:We can infer from the passage that_____.

A.Janet was so lovely a girl that Mr. Dawson couldn't resist her smiles

B.Janet and Amy were going to invite Mr. Dawson to listen to music and play games

C.Mr. Dawson was friendly to Amy because she always wore an invisible smile

D.it was Grandma's advice that helped bring Amy and Mr. Dawson closer小题3:The underlined word "contagious" in Paragraph 9 means _____.

A.infectious

B.supportive

C.moving

D.meaningful小题4:What is the main message that the writer intends to send us readers?

A.Always wear an invisible smile.

B.Smile whenever we can.

C.Try our best to transform others.

D.Pretend that we are happy even if we are not.

题型:判断题

安全问题忘记了,可以通过什么方式重新设置安全问题?

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无线电波是电磁波,而可见光不是电磁波。

题型:判断题

信号设备室外设备天窗修维修项目?

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