人的生长发育以及受损细胞的修复和更新，都离不开（    ）

已知△ABC∽△DEF，△ABC比△DEF的周长比为1：3，则△ABC与△DEF的面积之比为____ 

选用方框中的句子完成对话，其中有两项是多余的。
Li Lei: Excuse me. ____
Mr. Smith: Yes. And you are.. . ?
Li Lei: I’m Li Lei. Your friend Miss Wu is busy at the moment. She asks me to meet you. Welcome to Hangzhou, Mr. Smith.
Mr. Smith: Thank you.
Li Lei: By the way____ 
Mr. Smith: No. This is my second time. I came here in 1998 for the first time.
Li Lei:____
Mr. Smith: I like it very much. It’s very beautiful and famous in the world. And the people here are quite friendly.____
Li Lei: I’m glad you like the city. And now Hangzhou is becoming more and more beautiful.____
Mr. Smith: I think so. Thank you very much for meeting me.
Li Lei: It’s a pleasure.

①无数轻捷柔软的手指，弹奏出一首又一首优雅的小曲。（缩写句子）

②这山中的一切，哪个不是我的朋友？（改为陈述句）

③老桥，你如一位德高望重的老人。（改成感叹句）

④踏上一条幽径，我独自一个人单独去访问我的朋友。（修改病句）

⑤我愿意牵着你的手，一起到草虫的村落里去散散步。（改为反问句）