3，We have got quite used to them.

get used to = get accustomed to 习惯于新概念第二册

quite 加强了语气，用夸张的口吻表明事实

4，The first thing I saw when I entered the art gallery was a notice which said: 'Do not touch the exhibits. Some of them are dangerous!'

重点句型：The first thing... was a notice which said...首先是一个通知，上面写着…

say 用在notice 后面引出通知的具体内容，也可以用分词作定语：a notice saying…

5，Oddly shaped forms that are suspended from the ceiling and move in response to a gust of wind are quite familiar to everybody.

be suspended form = be hung from

in response to= as in reaction to

a gust of wind

e.g. a gust of anger\excitement\laughter 一阵短暂的爆发性的情感

be familiar to sb. 对某人来说很熟悉

e.g. The house is familiar to him.

e.g.  I don’t really remember where I have seen him before, but he looks very familiar to me.

区别词组：be familiar with sth. 熟悉，熟知

e.g. Are you familiar with the play of Shakespeare?

e.g. I am familiar with that book too.