在升旗结束后，小铭想利用所学数学知识测量学校旗杆高度，如图，旗杆的顶端垂下一绳子，将绳子拉直钉在地上，末端恰好至C处且与地面成60°角，小铭从绳子末端C处拿起绳子后退至E点，求旗杆AB的高度和小铭后退的距离．（单位：米，参考数据：$\sqrt{2}$≈1.41，$\sqrt{3}$≈1.73，结果保留一位小数）

根据句意、首字母提示或英文解释写出合适的单词。
（1）Don't play in the street. It's ____ (not safe).
（2） Your blue jeans____  (go well with) with your T-shirt very well.
（3） I'm a top student, and I have a healthy ____(the food you usually eat) and lifestyle.
（4） People usually think pigs are l____ . They say pigs do nothing but sleep and eat.
（5） We don't have e____ food for supper. Let’s buy some from the supermarket.
（6） A friend of mine is coming to v____  me this Saturday. I'm looking forward to seeing him.
（7） Every year we usually have a party to c____ Spring Festival.

懂得人工取火的远古居民是____。