复数$\frac{2i}{1+i}$的虚部为（　　）

2016年2月15日晚，备受瞩目的“感动中国2015年度人物评选”结果正式揭晓，安徽省宁国小伙，“最帅潜水员”官东获选2015年度感动中国十大人物。

官东1991年出生，在2015年6月2日“东方之星”沉船救援现场的潜水救援行动中，凭借过硬的潜水技术和机敏的临场反应，成功救出两名幸存者。关键时刻，他把潜水装备给了被困人员，自己险些被暗流冲走。

组办方给出的颁奖词是：“官东，天下英雄气，拯救‘东方之星’落水乘客的当代大学生。来不及思量，就一跃而入。冰冷，漆黑，缺氧，那是长江之下，最牵动人心的地方。‘别紧张，有我在’，轻声的安抚，稳住倾覆的船舱。摘下生命软管，那肩膀上剩下的只有担当。人们夸你帅，不仅仅指的是面庞。”

在探究影响电流做功大小的因素的实验中：

（1）用如图所示的电路可以来探究电功与____ 的关系．

（2）实验中提供“2.5V”和“3.8V”两种规格的灯泡若干，则你所选用的灯泡是____ 

（3）下面是某同学探究该实验的过程与记录，请帮他完成

①根据电路图连接电路

②闭合开关，调节滑片，观察到L₁比L₂亮，说明相同时间内电流通过____ 做功多，同时他还需要收集到的另一信息是____ 

③多次调节滑片的位置，重复步骤②

④综合分析实验的现象与数据得到的结论是：____ ．

   Let me tell you my pen friend Ivan. He is 12 years old. He likes playing football. He usually play football with his friends at weekends.
Ivan lives with his father and mother in a city in France. They have a dream home with five rooms, a swimming pool and a garden. They often have a party in the garden at weekends. They like to help their neighbours. His home is not near his school, so Ivan takes a bus for an hour and then walks for 10 minutes to school. There is a Basketball Club near his school. He likes play basketball in the club.
   Ivan's father is a worker. He is busy. Ivan's mother is a doctor. She is nice to the patients. Ivan wants to be a teacher when he grows up. I want to be a teacher, too. Every month Ivan writes two letters to me. He'll come to Suqian next year. We'll meet then.

生活在东西伯利亚的亚库特人，居住木屋，身着毛皮服装，运输工具是狗拉雪橇，这样的生活习惯主要受下列何种因素影响（   ）