问题 选择题

下列物质中,既有离子键,又有共价键的是

A.HCl

B.KOH

C.CaCl2

D.CH3COOH

答案

答案:B

题目分析:一般活泼的金属和活泼的非金属容易形成离子键,非金属元素的原子间容易形成共价键,据此可以判断。A、H和Cl都是非金属,氯化氢中只有共价键,A不正确;B、氢氧化钾是离子化合物,既有离子键,又有共价键,B正确;C、Ca和Cl分别是活泼的金属与非金属,二者形成的化学键是离子键,C不正确;D、醋酸是共价化合物,含有共价键,D不正确,答案选B。

阅读理解

On a hill 600 feet above the surrounding land, we watch the lines of rain move across the scene, the moon rise over the hills, and the stars appear in the sky. The views invite a long look from a comfortable chair in front of the wooden house.

Every window in our wooden house has a view, and the forest and lakes seldom look the same as the hour before. Each look reminds us where we are.

There is space for our three boys to play outside, to shoot arrows, collect tree seeds, build earth houses and climb trees.

Our kids have learned the names of the trees, and with the names have come familiarity and appreciation. As they tell all who show even a passing interest, maple(枫树)makes the best fighting sticks and white pines are the best climbing trees.

The air is clean and fresh. The water from the well has a pleasant taste, and it is perhaps the healthiest water our kids will ever drink. Though they have one glass a day of juice and the rest is water, they never say anything against that.

The seasons change just outside the door. We watch the maples turn every shade of yellow and red in the fall and note the poplars’(杨树)putting out the first green leaves of spring. The rainbow smelt fills the local steam as the ice gradually disappears, and the wood frogs start to sing in pools after being frozen for the winter. A family of birds rules our skies and flies over the lake.

小题1:What can be learned from Paragraph 2?

A.The scenes are colorful and changeable.

B.There are many windows in the wooden house.

C.The views remind us that we are in a wooden house.

D.The lakes outside the windows are quite different in color.小题2:By mentioning the names of the trees, the author aims to show that ______ .

A.the kids like playing in trees

B.the kids are very familiar with trees

C.the kids have learned much knowledge

D.the kids find trees useful learning tools小题3:What does the underlined sentence in the last paragraph mean?

A.The change of seasons is easily felt.

B.The seasons make the scenes change.

C.The weather often changes in the forest.

D.The door is a good position to enjoy changing seasons.小题4:What is the main purpose of the author writing the text?

A.To describe the beauty of the scene around the house.

B.To introduce her children’s happy life in the forest.

C.To show that living in the forest is healthful.

D.To share the joy of living in the nature.

单项选择题