如图所示为一磁流体发电机示意图，A、B是平行正对的金属板，等离_爱下问搜题

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问题选择题

如图所示为一磁流体发电机示意图，A、B是平行正对的金属板，等离子体（电离的气体，由自由电子和阳离子构成，整体呈电中性）从左侧进入，在t时间内有n个自由电子落在B板上，则关于R中的电流大小及方向判断正确的是（　　）

A．I= ，从上向下

B．I= ，从上向下

C．I= ，从下向上

D．I= ，从下向上

答案

答案：A

阅读理解

It was late in the afternoon. Several hundred villagers left their houses and gathered in the open air outside the village. They were staring __ __ at the mountain top in the distance. It was covered with __ __ —beautiful and dangerous.
The huge mountain is called Matterhorn. Mountain climbers had __ __ the top, using the southern route. But no one had __ __ dared to try a winter climbing up the northern side. But now one man was daring to try the __ __ route— the northern route, which was more difficult. He was Walter Bonatti, a great mountain climber from Italy.
For two days he had climbed. The village people had watched him __ __. Now they were waiting to see his ____. If he planned to __ __ the next day, he would light a green signal. A red light would mean that he was __ __.
A tiny green light __ __ high on the mountain side. Bonatti was not giving up! The people __ __.
The next day he continued his way upward. He was so lonely and so __ __！But he would not give up. Again that night he lit the __ __ light.
In the morning, Bonatti __ __. He could not see the top, but he knew he was __ __ there. Though the climb was painful, he moved up.
Bonatti had spent months __ __ for the climb. Was the training enough? Did he have the strength and ____ to climb to the top?
He was finally at the top! News about his __ __ was radioed to the world.
The trip __ __ the southern route was easy. He was warmly welcomed in the village. He had done the “ __ __ ”，and would be well remembered as a climber of all time.

B．ice and snow

C．green trees

A．turning back

C．staying away

单项选择题

下列关于早期胃癌的描述，错误的是（）。

A.病变局限于黏膜层

B.病变局限于黏膜层或黏膜下层

C.病变的大小与早期胃癌的定义无关

D.有无周围淋巴结转移与早期胃癌的定义无关

E.病变仅累及黏膜肌层