解释下列词语。

①肃然起敬：

②糟蹋：

③应许：

④庸碌：                                                       

某同学调节托盘天平平衡时，发现指针停在分度盘的右侧．要使天平平衡，应将横梁右端的平衡螺母向　____ 　（选填“左”或“右”）移动；当他用天平测物体质量时，发现指针偏向分度盘的左侧，这时应该在天平右盘中　____ 　（选填“增加”或“减少”）砝码；当他在天平右盘中放入50 g、20 g和5 g的砝码各一个，并将游码拨到如图所示的位置时，指针恰好指在分度盘的中央，则被测物体的质量为　____ 　．

短文改错

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处错误，每句中最多有两处。错误涉及一个单词的增加、删除或修改。

增加：在缺词处加一个漏字符号(Λ)，并在其下面写出该加的词。

删除：把多余的词用斜线(＼)划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：

1）每处错误及其修改均仅限一词；

2）只允许修改10处，多者(从第11处起)不计分。

My brother used to ask me question whenever he did his homework, that made me annoyed. But every time he accepted my explanations I feel that I was the smartest person in the world. Answered his questions, I always liked to say that he was so stupid to solve such simple problems.

Last week both of them got the report cards from our school. Unexpectedly, I got a lot of Bs, though he got As. To make things worse, all that day my brother screamed how foolish it was for me not to ask questions! I could say nothing but admit that he was right. I have never made a fun of him since then.

自身免疫病产生的原因是 （   ）