如图，点A是反比例函数y= $\frac{4}{x}$ （x＞0）图象上一点，直线y=kx+b过点A并且与两坐标轴分别交于点B，C，过点A作AD⊥x轴，垂足为D，连接DC，若△BOC的面积是4，则△DOC的面积是____．

对羟基苯甲酸丁酯(俗称尼泊金丁酯)可用作防腐剂，对酵母和霉菌有很强的抑制作用，工业上常用对羟基苯甲酸与丁醇在浓硫酸催化下进行酯化反应而制得。以下是某课题组开发的从廉价、易得的化工原料出发制备对羟基苯甲酸丁酯的合成路线：

已知以下信息：

①通常在同一个碳原子上连有两个羟基不稳定，易脱水形成羰基；

②D可与银氨溶液反应生成银镜；

③F的核磁共振氢谱表明其有两种不同化学环境的氢，且峰面积比为1∶1。

回答下列问题：

补全对话, 其中有两个多余选项。

A: Hello, Tim!

B: Hello, Alice! Come in and have a seat. ____ 

A: Thank you. I'm coming to say goodbye to you. ____ 

B: Really?____ 

A: I'm going to an English Summer Camp there.

B: What will you do at camp?

A: ____ 

B: I'm sure you will speak English much better. How long will you stay there?

A: About ten days.

B: ____ 

A: Sounds great. ____  

B: The Summer Palace, the Great Wall and some other interesting places. All of them are well worth visiting.

A: Wonderful! But I don't know how I can get to these places.

B: Don't worry. ____ By the way, don't forget to buy a map of Beijing.

A: Thank you for your advice.

B: ____ Enjoy yourself!

A. How about visiting some places of interest in your spare time? B. What is the purpose of your visit? C. The tourist bus can take you anywhere. D. What places do you think I should visit? E. You're welcome. F. I will practise my spoken English in a new way. G. See you later. H. Make yourself at home. I. I'm going to Beijing tomorrow. J. I'm going to have a rest in Nanjing.

多数同学家里都有调光台灯、调速电风扇，过去是用变压器来实现上述调节的，缺点是成本高、体积大、效率低，且不能任意调节灯的亮度或风扇的转速．现在的调光台灯、调速电风扇是用可控硅电子元件来实现调节的，如图4所示为一个经过双向可控硅电子元件调节后加在电灯上的电压，即在正弦式电流的每一个周期中，前面的被截去，从而改变了电灯上的电压．那么现在电灯上的电压为      (　　)

设随机变量ξ服从正态分布N（0，1），P（ξ＞1）=0.2，则P（﹣1＜ξ＜0）等于____．