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问题 问答题

小明在“探究凸透镜成像规律”的实验中，记录并绘制了如图所示像距v跟物距u之间的关系图象．该凸透镜的焦距f=______cm，当物距u=15cm时，此时物体所成像的性质是______像．

答案

当物距等于像距等于2倍焦距时，物体成等大倒立的实像，由图可知，u=v=2f=20cm，

此时的f=10cm，故答案为：10cm，

已知焦距为10cm，则物距为15cm，因当物距介于1倍焦距与2倍焦距之间时，成倒立放大的实像，

故答案为：倒立放大的实．

阅读理解
Dogs are considered as man’s best friend. But what about cats? Sometimes cats can make equally wonderful friends. The following is a comparison of the two animals.
A Friend Helps You When You’re Sick
Dogs
When Catherine lay down on the sofa, Pepe stared(盯) into her eyes and kept sniffing(嗅). After being pushed away, he suddenly jumped onto her chest. That’s when Catherine felt a pain that made her visit a doctor, and a fast-growing cancer was found. Months later, however, Pepe started staring and sniffing again. It seemed strange, but sure enough, Catherine’s cancer had spread.
Cats
When Tee sits and stares directly into her face, Alana immediately finds a chair. That’s because Tee is warning her that she is about to faint(昏倒), which can happen as often as three times a day. But Alana won’t get hurt if she sits down. Not only does Tee warn Alana, but also her husband. Then the cat stays with Alana until she recovers.
A Friend Saves Your Life
Dogs
Ryan fell into the water by accident. The river was full of melted snow, and Ryan was very cold and his body temperature was dropping dangerously low. Luckily, he was found by Chelsea, who was playing with her dog, Zion. “Zion knew the boy was in trouble,” says Chelsea. “Ryan grabbed onto the dog’s collar, and Zion just turned around and came straight back to the shore.”
Cats
“I was napping in my bedroom, and then I was woken by Joey screaming and running back and forth,” says Bernice. Then she found herself surrounded by smoke. With Joey alongside her, she managed to get out of the door. By then, flames(火焰) were shooting up from the basement.
“I found him in a mailbox when he was young and now I feel very fortune. Without him, I’d have probably died in the smoke.”
小题1:When Alana is about to faint, Tee will ____________.
A．stare at her and keep sniffing
B．jump onto her chest suddenly
C．sit and stare directly into her face
D．scream and run back and forth
小题2:What can we learn about Ryan?
A．He likes swimming in rivers.
B．He has a lovely dog, Zion.
C．Chelsea helped him swim back to the shore.
D．He was in danger when he was found by Chelsea.
小题3:What happened to Bernice?
A．She was badly hurt in a big fire.
B．She met the brave cat, Joey, in a big fire.
C．A fire broke out when she was napping.
D．She ran out of the burning house with the help of firemen.
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多项选择题

关于员工福利制度的说法，正确的有( )。

A．福利是企业通过设置各种补贴为员工生活提供方便的一种非直接支付

B．福利的提供与员工的工作绩效和贡献有关

C．福利具有激励员工和促使员工忠实于企业的作用

D．福利既可以是货币形式的，也可以是实物形式的

E．企业为员工发放劳动保护用品属于保险福利
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