问题 选择题

核反应中会产生碘原子I-131,而我们生活中常见是含I-127的碘及碘的化合物,下列说法正确的是

A.1-131和I-127互为同位素

B.食盐中含碘物质是碘化钾

C.分离氯化钠和碘单质可以用过滤的方法

D.I-131和I-127化学性质不同

答案

答案:A

本题可采用排除法。食盐中的碘是以碘酸钾的形式加入的,因其比碘化钾更稳定;分离氯化钠和碘单质应用加热升化法;同位素的化学性质几乎完全相同,因为核外电子排布相同。故选A。

完形填空

[1]A homeless man who wanders around in the streets of the Bronx singing soft R&B songs has become famous thanks to his talent and YouTube.

[2]James Percell, 49, was discovered by music manager, Kenneth Williams, who decided to help him get off the streets. In one video, Kenneth Williams speaks to the camera and explains ______________.  "I went to the Bronx to visit my family, and I ran into this homeless brother," he says. "His voice is very beautiful."

[3]Mr. Percell has become famous on YouTube, where more than a million people have heard his golden voice, and many producers and filmmakers have already expressed their eagerness to work with him.

[4]Mr. Percell says he has been homeless for a few years and neglects everything for the love of music in an attempt to develop his career, he has cried out for The Voice and the X- Factor singing competitions. But the judges didn’t contact him after they found out that he was homeless.

[5]He now has a MySpace page and Facebook fan page, which are used to share his songs with his fans. He has written many songs, one of which is Everything Must Change, written for Michael Jackson. He hopes that his songs will help the world know his story and life struggle to make it as a singer, and also hopes that social media can give him a fighting chance to finally make his dream come true.

小题1:What has made James Percell famous?(no more than 8 words)

______________________________________________________________________

小题2:Fill in the blank with the appropriate words.(no more than 5 words)

In one video, Kenneth Williams speaks to the camera and explains _______________________________.

小题3:What is the main idea of the third paragraph?(no more than 7 words)

_______________________________________________________________________

小题4:Why did the judges from some singing competitions refuse to contact James Percell?

(no more than 5 words)

_________________________________________________________________________

小题5:What does the word "which" probably refer to?(Line 2, Paragraph 5)

(no more than 6 words)

选择题