（4分）下列各物质：①O2、O3②H2、D2、T2③12C、14C ④⑤ 互为同_爱下问搜题

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问题填空题

（4分）下列各物质：①O₂、O₃②H₂、D₂、T₂③¹²C、¹⁴C

④ ⑤

互为同分异构体的是（填序号，下同）；互为同位素的是

互为同素异形体的是；是同一种分子的是

答案

4 3 1 5

同分异构体是指分子式相同而结构不同的化合物。同位素是指质子数相同而质量数不同的同一元素的不同核素。由同一种元素形成的不同单质互为同素异形体。结构和性质均完全相同的是由÷同一种分子。

完形填空

Years ago, there was a very wealthy man who, with his devoted young son, shared a passion for art collecting. Together, they traveled around the world, adding only the   36  art treasures to their collection.
One year, as winter approached,   37  engulfed (吞没) the nation, and the young man left to 38  his country. After only a few short weeks, his father received a telegram. His beloved son was   39  in action. The art collector   40  awaited more news,  41  he would never see his son again. Within days, his fears were   42  . The young man had died while rushing a fellow soldier to a doctor.
Upset and   43  , the old man faced the coming Christmas holidays with sadness. On Christmas morning, a knock on the door awakened the   44  old man. As he opened the door, he was greeted by a   45  with a large package in his hands.
He introduced himself to the old man by saying,“ I was a   46  of your son. I was the one he was 47  when he died. May I come in for a few moments? I have something to show you.”
As the two began to   48  , the soldier told of how the man's son had told everyone of his, not to mention his father's   49  of fine art. “I am no   50  ,” said the soldier, “but I want to give you this.”
As the old man unwrapped the package, he saw a portrait his son. Though the world would   51 consider it the work of a genius, the painting featured the young man's face   52  striking detail.
Overcome with emotion, the man   53  the soldier. After the soldier had left, the old man put the painting above the fireplace, pushing   54  thousands of dollars worth of art. His task completed, the old man sat in his chair and spent Christmas gazing at the   55  he had been given.

B．photographer

A．description

D．understanding

B．businessman

单项选择题

中压总线的电压为（）。

A.110VAC

B.110DC

C.380VAC

D.220VAC