婴幼儿溢泪主要的原因是（） A.结膜炎 B.先天性泪小点闭锁 C.先天性泪小管闭锁

John H. Johnson was born in a black family in Arkansas City in 1918. His father died in an accident when John was six. He was reaching the high school age, but his hometown offered no high school for blacks.

Luckily he had a strong-willed caring mother. John remembered that his mother told him many times, “Son，you can be anything you want really to be if you just believe.” She told him not to depend on others，including his mother. “You have to earn success,” she said. “All the people who work hard don’t succeed, but the only people who do succeed are those who work hard.”

These words came from a woman with less than a third grade education. She also knew that believing and hard work don’t mean everything. So she worked hard as a cook for two years to save enough to take her son, who was then 15，to Chicago.

Chicago in 1933 was not the promised land that black southerners were looking for. John’s mother and stepfather could not find work. But here John could go to school, and here he learned the power of words — as an editor of the newspaper and yearbook at Du Sable High School. His wish was to publish a magazine for blacks.

While others discouraged (使气馁) him, John’s mother offered him more words to live by: “Nothing beats a failure but a try.” She also let him pawn（典当）her furniture to get the ＄500 he needed to start the Negro magazine.

It is natural that difficulties and failures followed John closely until he became very successful. He always keeps his mother’s words in mind: “Son, failure is not in your vocabulary!”

Now John H. Johnson is one of the 400 richest people in America — worth $150 million.

小题1: John’s father died in ________.

A．1922

B．1933

C．1924

D．1923小题2:John’s mother decided to move to Chicago because _______.

A．his father died when John was very young

B．life was too hard for them to stay on in their hometown

C．there were no schools for black people in their hometown

D．John needed more education badly小题3: John’s mother ________．

A．didn’t believe in or depend on others

B．thought no one could succeed without working hard

C．believed one would succeed without working hard

D．thought one could be whatever one wanted to be小题4:The story mainly tells us ________ .

A．about the spiritual support John’s mother gave him

B．how John H. Johnson became successful

C．about the importance of a good education

D．about the key to success for blacks

女童，5岁，右下第二乳磨牙咬合面深龋洞，腐质去净后洞底在牙本质浅层，治疗方法是（）

A.银汞合金充填

B.玻璃离子水门汀充填

C.复合树脂充填

D.金属成品冠

E.树脂嵌体

设[*]，则k取何值时：
(Ⅰ) β可由α₁，α₂，α₃唯一线性表示；
(Ⅱ) β不可由α₁，α₂，α₃线性表示；
(Ⅲ) β可由α₁，α₂，α₃线性表示，但表示法不唯一，并求出一般表达式．

屋面卷材铺贴时，应按（）的顺序。

A.先高跨后低跨

B.先低跨后高跨

C.先近后远

D.先远后近

E.先做好泛水，然后铺设大屋面

联邦制国家中的中央政府与各组成单位的权力划分（）。

A.由中央政府决定

B.经中央政府与各组成单位协商后由宪法规定

C.由独立的最高法院决定

D.由各组成单位决定