问题 填空题

你根据哪些性质区别下列各组物质.

①酒精和水______;    ②冰和水______;   ③食盐和淀粉______;   ④氨水和碘酒______;

⑤铜丝和铁丝______.

答案

①酒精有酒精的气味,水是无味的,所以通过闻气味就能鉴别开;②冰是水的固态,属于固体,水是液体,可以通过观察物质状态来鉴别;③碘遇淀粉变蓝,所以用碘可以鉴别;④氨水具有刺激性气味,碘酒是无味的液体;氨水是无色液体,碘酒是紫黑色,所以通过气味或观察颜色进行鉴别;⑤铜丝是紫红色,铁丝是银白色,所以可以通过观察颜色进行鉴别.

故答案为:①气味  ②状态   ③碘  ④气味(颜色) ⑤颜色;

多项选择题
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A lazy Susan is an addition to a table that is designed to assist in moving food from one person to another while dining. This is achieved through the use of a turntable (转盘), which usually moves the food in a circle when it is pushed by those at the table. In this way, the food never has to be picked up and passed around the table. Instead, it remains in place on the lazy Susan.

A lazy Susan may also be a part of a kitchen cabinet (橱柜). In this sense, the lazy Susan is a type of shelving unit within the cabinet that is able to turn around its axis(轴心) . One may turn the lazy Susan in order to find certain goods in storage. From the outside, a lazy Susan appears to be two cabinets that are located at a right angle (直角) to each another. When one of these cabinets is pushed, however, both doors move and the lazy Susan is revealed inside.

It is believed that Thomas Jefferson invented the lazy Susan in the 18th century, though it was called “dumbwaiter” at that time. It is said that Jefferson invented the lazy Susan because his daughter complained she was always served last at table and, as a result, never found herself full when leaving the table. Others believe that Thomas Edison was the inventor, as he is believed to have invented the turntable for his phonograph (留声机). The turntable may have developed into the lazy Susan later.

Regardless of who invented it, it wasn’t until 1917 that the term “lazy Susan” was used in an advertisement for the invention. In Britain, however, the term “dumbwaiter” is still used rather than “lazy Susan”. The reason for the naming of it is still a mystery. One theory is that it was named after either Jefferson’s or Edison’s daughter, both of whom were named Susan.

小题1:What is a “lazy Susan”?

A.A waitress

B.A convenient tool

C.A table

D.A cabinet小题2:According to those who believed Thomas Jefferson invented the lazy Susan, _______.

A.his daughter was very lazy

B.the lazy Susan didn’t exist until the 18th century

C.Thomas Edison was his friend

D.Thomas Edison didn’t invent the phonograph小题3:We can learn from the last paragraph that ___________.

A.the lazy Susan can work by itself

B.the lazy Susan was named after Thomas Edison’s daughter

C.how the lazy Susan got its name remains unknown

D.the lazy Susan was invented in Britain小题4: The writer wrote the passage mainly to _________.

A.discuss how the lazy Susan was named

B.teach us how to make a lazy Susan

C.introduce Thomas Edison’s inventions

D.tell us what a lazy Susan is and its origin