数列$\left\{a_n\right\}$中，如果$a_n=2n-1$(n＝1，2，3，…) ，那么这个数列是(     )．

Complete the sentences with the given words in their proper forms.(用括号中所给单词的适当形式完成下列句子。每空格限填一词)

Some people like reading on Wechat, but ____  don't. (other)

Cut the strawberries into pieces and put ____  into the yogurt. (they)

The day was ____ , but the sun was trying to come through. (cloud)

I'm thankful to the teacher for her ____ on my interview. (suggest)

It's our responsibility to make the sky ____ than before. (clear)

Education is one of the most powerful ways to ____ one's mind. (rich)

I think it's ____ to judge a person before you really know him. (fair)

____ , the famous temple was not damaged in the earthquake. (luck)

单项式﹣3πxy²z³的系数和次数分别是（　　）

阅读文章，解答问题。

从小丘西行百二十步，隔篁竹，闻水声，如鸣佩环，心乐之。伐竹取道，下见小潭，水尤清洌。全石以为底，近岸，卷石底以出，为坻，为屿，为嵁，为岩。青树翠蔓，蒙络摇缀，参差披拂。

潭中鱼可百许头，皆若空游无所依。日光下彻，影布石上，佁然不动；俶尔远逝，往来翕忽，似与游者相乐。

潭西南而望，斗折蛇行，明灭可见。其岸势犬牙差互，不可知其源。

坐潭上，四面竹树环合，寂寥无人，凄神寒骨，悄怆幽邃。以其境过清，不可久居，乃记之而去。

同游者：吴武陵，龚古，余弟宗玄。隶而从者，崔氏二小生：曰恕己，曰奉壹。