下列关于进程间通信的描述中，不正确的是 A．进程互斥是指每次只允许一个进程使用临界资

求适合下列条件的抛物线的标准方程：

（1）顶点在原点，对称轴为坐标轴，顶点到准线的距离为4；

（2）顶点是双曲线16x²-9y²=144的中心，准线过双曲线的左顶点，且垂直于坐标轴．

Ruben lived in a small village. There was no school there and he had to study in a school in the town. It was nearly five kilometres away from his village. His father couldn't buy a bike for him and he had to go to school on foot. He got up early in the morning. Usually he had to run there in order not to miss the first class. He kept running every day and it was helpful to him. He's strong and tall now and he ran faster than any other man in his village. He took part in several sports meetings and won some medals. The young man is proud of（以……自豪）it and always wants to have a race with others.

One day his mother was ill and his father told him to buy some medicine for headache in the town. The young man got there soon. There were many people in the chemist's shop while he was waiting there. And when his turn came, he could't find his money. An old woman hinted（暗示）a young man had stolen it. He saw the thief had already left the shop. He ran towards him quickly. The thief found it and began to run. He was happy and tried to catch up with him.

“Let's have a race and see who will run faster, ”Ruben called out behind.

Soon after that he caught up with the thief. But he didn't stop and went on running. At a crossing one of his friends asked, “What are you running for, Ruben? ”

“I'm running after（追）a thief. ”

“Where's the thief, then? ”

“He wants to show that he'll run faster than me, but he's fallen behind!”

小题1: Ruben had to run to school because ____.    [    ]

A．he had no bike

B．he hoped to win some medals

C．his village was a little far from the school

D．he was afraid to be late for class小题2:____ , so he won some medals.     [    ]

A．Ruben is good at running

B．Ruben went to school on time

C．Ruben often took part in the sports meetings.

D．Ruben likes to have a race with others小题3:The phrase “a chemist's shop”in the story means ____.  [    ]

A．化工商店

B．药店

C．化工厂

D．制药厂小题4:Ruben's money was stolen ____.   [    ]

A．on his way to the town

B．before he went in the shop

C．when he was waiting in the shop

D．after he had left the shop小题5:Ruben was happy because ____.   [    ]

A．he could easily catch the thief

B．he had a chance（机会）to have a race

C．he knew who had stolen his money

D．he would win another medal that day

白癜风在稳定期，白斑停止发展，境界清楚，边缘有（）。

下列关于Crohn病的营养治疗原则，正确的一组是（）。

A.低热能、低脂肪、低蛋白

B.高热能、高维生素、高蛋白

C.高热能、高脂肪、低蛋白

D.高热能、高脂肪、高糖类

E.低热能、高蛋白、低脂肪

设，当x→0时，与f(x)等价的无穷小量是（）。

A．

B．x⁴

C．2x⁵

D．