关于重症肌无力描述错误的是A．伴有胸腺萎缩 B．可见合并胸腺瘤 C．与胸腺异常有关

阅读下面短文，用括号内所给动词的适当形式填空，必要时可加助动词或情态动词 。 

     "Tom? Are you in bed yet?" called Mrs. Green.There was no answer. Mrs. Green put down her book and

went to her 14-year-old song room.Tom 1______(sit) in front of a bright computer screen on which a

motorbike was running fast.

     "Oh, Tom.. How long 2______ you ______ (play) on that computer? You must stop now.it's half past

eleven.If you don't go to bed soon, you'll be very tired tomorrow," said Mrs. Green.

     "But I've nearly won the game," said Tom to Mrs. Green. She 3______ (see) the excitement on his face.

She 4______ (sit) down beside him.You're always playing on the computer. You 5______ (spend) more time

on this machine than on your homework.

     Today more and more families have computers. Parents hope computers can help their children 6______

(improve) their study at school.But, many of their children use computers to play games, to watch videos,

instead of 7______ (study). We often see that computer game houses 8______ (crowd) with people, especially

young boys.They spend a lot of money competing with the computerized machines.

     The more they lose, the more they want 9______ (win). The result is that they don't want to work or study.

     In some other countries, even scientists hate computers. They say computers cause millions of people to

lose their jobs or cause them a lot of trouble. Computer game addiction 10______ (be) a serious problem in

social life. Something has to be done to solve the problem.

什么是集尘面积？

HDIL测井时，一方面要求仪器应避免来回摆动，另一方面也要求井眼尺寸（）。

A、不变

B、可变

C、可以有剧烈的变化

D、不应有剧烈的变化

关于快速眼动睡眠，正确的说法是（）。

A.大多数发生在睡眠后期

B.大多数发生在睡眠早期

C.持续时间越来越长

D.持续时间越来越短

（）用于吊装较小柱子或起重机械的吊杆受长度限制而无法将构件垂直吊起时。

A.单机斜吊法

B.单机旋转吊装法

C.双机滑行抬吊法

D.单机滑行吊装法