向氯化铜溶液加入一定量的锌粉充分反应,下列情况中可能出现的是( )
① 溶液中有Zn2+、Cu2+,不溶物为Cu ② 溶液中有 Zn2+、Cu2+,不溶物为Zn
③ 溶液中只有Zn2+,不溶物为Zn ④ 溶液中只有Zn2+,不溶物为 Zn、Cu
A:①③
B:②③
C:①④
D:③④
下表反映了我国在“一五”时期各部门的投资比例。由此可见当时我国( )
部门
工业
交通运输
农林水利
文化教育
其他
投资比例
58.2%
19.2%
7.6%
7.2%
7.8%
1881年中国唐胥铁路建成通车,但清政府却让骡马充当火车头,出现了“马拉火车”的天下奇闻。这反映了清政府( )
阅读短文,然后根据要求完成任务。 Do you carry too much on the way to school or home? Don’t worry.Try e-readers (电子阅读器) and say goodbye to your heavy schoolbag. An e-reader has the memory space to hold hundreds of books.So people want to (A)扔掉沉书包 and read with small, light e-readers.For example,Cushing Academy,a high school in Massachusetts,USA,replaced (替换) most of the 20,000 books in (B) its library last summer.Teachers and students will use e-readers instead. Most e-readers are thin and weigh less than 500g.They can download (下载) an e-book in 60 seconds.“It’s (C) so easy.You can have a lot of books right at your fingers!” said Meghan Chensusky. Chinese schoolchildren are also trying e-readers.At the Shanghai World Expo (世博会),an e-schoolbag is now on show.It is a special e-reader.Students can use it to download textbooks from the school servers (服务器).(D)It can also send and receive homework.Some Schools in Beijing and Shanghai have tried this e-schoolbag for a few years.“It’s excellent.I (E)don’t have to carry a heaw schoolbag anymore,”said Xiao Qi,15,Beijing. New e-readers are not just for reading.They have Wi-Fi and multimedia (无线电视和多媒体).Parents worry that these may hurt their children’s study habits. “I think Wi-Fi is not necessary for kids,”said Zeng Wenwen,43, Beijing.