问题 填空题

由负序电压元件与低电压元件组成的复合电压元件构成复合电压闭锁过流保护,其动作条件是低电压元件或负序电压元件动作,同时()动作,保护才启动出口继电器。

答案

参考答案:电流元件

阅读理解

Mr. Brown was going away for a week. Before he left, he said to his son, “If anyone comes to visit me, tell him that your father is away on business, and will be back in a week, then be sure to ask him to sit down for a cup of tea.”

“OK, Dad,” said his son. Mr. Brown was afraid his son wouldn’t remember this, so he wrote these words down on a piece of paper and gave it to him. His son put the paper into his small pocket. He took it out and looked at it every now and then.

Four days passed, but no one came to see his father. The boy thought that no one would come and that the piece of paper was of no more use to him, so he burnt it.

The next afternoon, someone knocked at the door. The boy opened it. A man was standing at the door and said, “Is your father at home?” The boy put his hand into his pocket at once for the piece of paper. He could not find it. He suddenly remembered he had burnt it, so he shouted, “No more.”

The man was very surprised. He asked, “No more? I met your father last week. When did it happen?”“Burnt yesterday evening.”

小题1:Mr Brown told his son that            

A.he would be away from home for four days

B.he would be back in seven days

C.he would be back in a month

D.he liked a cup of tea小题2:Mr Brown wrote the words down on           

A.the wall

B.the door

C.a piece of paper

D.his son’s pocket小题3:A man came to visit the boy’s father on          day.

A.the second

B.the third

C.the fourth

D.the fifth小题4:The man was very surprised because           

A.he thought the child’s father was burnt

B.the child didn’t ask him to sit down

C.the child gave him a cup of tea

D.he couldn’t find that piece of paper

单项选择题