与圆$x^2+y^2=1$及圆$x^2+y^2-8x+12=0$都相外切的圆的圆心在(  )

按拼音写汉字

(上车)____ ____ 

从对话后的方框中选择适当的选项补全对话
Ted: What's the best restaurant in town?
Kay: What kind of food do you like?
Ted: ____ 
Kay: Well, the French Deli is really good.
Ted: ____ 
Kay_: Yes, it's the most expensive restaurant in town. But it has the best service, too.
Ted:____ 
Kay: It's cheaper than the French Deli, but the food is kind of boring.
Ted: ____ 
Kay: Oh, that's a new place. It's the most popular restaurant in town.
Ted: Is the food good?
Kay: Yeah, if you like hot curry.
Ted:Yeah. I love it! Let' s go there.

下列关于乙酸的说法中，正确的是（　　）

①乙酸易溶于水和乙醇，其水溶液能导电　

②无水乙酸又称为冰醋酸，它是纯净物

③乙酸分子里有四个氢原子，所以它不是一元酸　

④乙酸是一种重要的有机酸，常温下乙酸是有刺激性气味的液体　

⑤1mol乙酸与足量乙醇在浓硫酸作用下可生成88g乙酸乙酯

⑥食醋中含有乙酸，乙酸可由乙醇氧化得到．