问题 探究题

在“做几个有趣的影子游戏”的活动中,小华发现,影子的大小随着光源与物体间距离的变化而变化,那么它们之间究竟有什么关系呢?小华决定借助如图所示实验装置来探究这个问题。

实验中,把手电筒正对黑板擦由近及远先后放在距离黑板擦不同位置,保持其它因素不变,分别测量影子在墙面上的高度,记录数据如下表:

(1)分析数据他们发现,若保持其它因素不变,当手电筒由近处逐渐远离黑板擦时,影子的高度随之 _________________。

(2)为了进一步发现其中的规律,他们根据数据绘制了影子高度H随手电筒到黑板擦距离L变化的图像,由图像可知,当手电筒到黑板擦的距离L=35cm时,影子的高度H大致是_____________cm。

(3)当手电筒距黑板擦较远时,观察图像的变化趋势发现,影子变小得________(选填“快”或“慢”);当手电筒距离黑板擦足够远时,影子大小将__________。

答案

(1)减小。

(2)15.3~15.7均正确

(3)慢,基本不变

阅读理解

D

When I was growing up, I had an old neighbor, Dr. Gibbs. He didn’t look like any doctor I’d ever known. He never invited us to play in his yard, but he was a very kind person.

When Dr. Gibbs wasn’t saving lives, he was planting trees. He owned a large field and wanted to make it a forest.

The good doctor had some interesting ideas about planting trees. He never watered his new trees. Once I asked why. He said that watering plants spoiled (宠坏)them, and that if you watered them, each baby tree would grow weaker and weaker, so you had to make things difficult for them and pick out the weaker trees early on.

He talked about how watering trees made for shallow(浅的) roots, and the trees that weren’t watered had to grow deep roots in search of water under the earth by themselves. Deep roots were very important.

So he never watered his trees. He’d planted an oak and, instead of watering it every morning, he’d beat it with a rolled-up newspaper. I asked him why he did that, and he said it was to get the tree’s attention.

Dr. Gibbs died several years after I left home. Every now and then, I walked by his house and looked at the trees that I watched him plant about twenty-five years ago. They’re very big and strong now.

I planted some trees a few years back and carried water to them for a whole summer. After two years of caring too much, whenever a cold wind blows in, they shake a lot.

Every night before I go to bed, I check on my two sons. Mostly I pray(祈祷) that their lives will be easy. But lately I’ve been thinking that it’s time to change my prayer. I know my children are going to face difficulties. There’s always a cold wind blowing somewhere, so what we need to do is to pray for roots that reach deep into the brave heart, so when the rains fall and the winds blow, we could face it strongly and won’t be beaten down.

小题1: We know from the reading the doctor _________.

A.didn’t know how to plant trees at all

B.wasn’t good at his own medical job

C.had his own ways of planting trees

D.had nothing to do but plant trees小题2: When Dr. Gibbs said, “...pick out the weaker trees early on.” he means that ______.

A.some weak trees would be easily found out at the beginning

B.he would choose the weak trees to water earlier

C.the weak trees would be sent to his patients later

D.he would not plant weak trees so early anymore小题3:The passage tells us that the writer _______.

A.should beat his trees with a rolled-up newspaper

B.didn’t often water his trees

C.didn’t have a large field

D.took too much care of his tree小题4: The writer wants to change his prayer, hoping that ________.

A.his trees will be stronger than Dr. Gibbs

B.his trees will not be beaten down

C.his sons will be better at planting trees

D.his sons will be able to face difficulties小题5:Which can be the best title of the reading?

A.Watering Trees

B.Growing Roots

C.Doctors and his Neighbor

D.Father and his Children

选择题