2016年1月2日，在上海地铁某车厢内一名女乘客吃泡椒凤爪并随地吐骨头的行为，遭到了周围乘客的指责。该件事说明（    ）

①触碰道德底线的事情不做                  ②我们要知廉耻，懂荣辱

③“行己有耻”需要我们有知耻之心       ④受人尊重的奥秘是忍让

计算a+(－a)的结果是（    ）

《静默草原》作者____，____族。1958年生。内蒙古赤峰市人。中国作协会员。我国著名的蒙古族作家、儿童作家。从1981年开始发表作品，小说、散文、诗歌、报告文学等均多次获奖，近年以散文创作为主，著有《掌心化雪》、《惟一的橘子惟一的灯》等散文集13部，被评为辽宁省优秀青年作家，曾获人民文学散文奖、文汇报笔会奖、中国新闻奖金奖。

    What's this? It's letter(字母)P. What colour is it? It's green. What's this and what colour is it? It's letter E. It's brown. What's this letter? It's letter N. It's red. P—E—N. Is it“pen”? Yes, it is.

    I have a blue pen in my pencil case(铅笔盒). My pencil case is orange. This is my book. It's my Chinese book. It's in my bag. My bag is black. Look! The bag is on the chair. The chair is yellow. It's my chair. It's nice. I like it.

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