讲究文明礼貌是中华民族的优良传统。 因为讲文明、有礼貌（　　）

①有利于战胜任何困难

②有利于加强个人的品德修养

③有利于人与人之间建立亲切、和睦的关系

④有利于社会的安定团结。

根据下面的对话内容，从对话前的选项中选出最佳选项填入空白处，将代号填入空白处。选项中有一个多余选项。

A: It's very late. Are you still on the computer?
B: Well, yes. ____ 
A: What kind of e-mails?
B: Some are messages from my friends and some are from the relatives.
A: Do you have to write them back right away?
B:____  Usually people want a quick reply.
A:____ 
B: I've already had 40 people's addresses in my address book!____ 
A:____  E-mail is really very convenient(方便的).

世界各地同一城市气温最高的时间一般是在 （　　）