问题 不定项选择题

天然存在的金属钫(Fr)极微量。它的21个已知同位素都有放射性。它是碱金属元素中最重的元素。根据它在周期表中的位置预言其性质,其中不正确的是[ ]

A.在已知元素中具有最大的原子半径

B.在空气中燃烧时生成氧化物Fr2O

C.氧化物对应的水化物是极强的碱

D.其单质的熔点比金属钠的熔点高

答案

BD

阅读理解

Leonardo da Vinci began painting the Mona Lisa in 1503. He was working on an important painting for a church at the time, but the church painting was not going well. An Italian businessman asked da Vinci to paint a picture of the businessman’s second wife. This is the woman who can be seen in the Mona Lisa.

All in all, the Mona Lisa is a very good example of da Vinci’s work. Da Vinci uses darkness and light in a clever way in the painting.

Da Vinci loved science and math. Right away a person can see that there is a lot of geometry (几何) in the Mona Lisa. The face of Mona Lisa is made of many circles and round shapes like balls. Even her smile can be seen as a small part of a large circle.

The woman in the painting is sitting on a balcony, and mountains can be seen behind her. Da Vinci loved to study rocks and mountains, so these can be seen over and over again in his other paintings.

The woman is sitting with her knees to the side. Her head is turned to look out of the painting. Her hands are held together in front of her. This way of sitting is now used by many artists when they are painting a picture of a man or woman today.

小题1:Who painted the Mona Lisa?

A.A businessman.

B.The second wife.

C.A man in the church.

D.Da Vinci.小题2:The woman in the painting is           .

A.standing in a garden

B.sitting on a balcony

C.standing in front of her house

D.at the foot of a mountain小题3:Da Vinci loved to study all of the following things except            .

A.the way people sit

B.science and math

C.mountains

D.rocks

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