humans are social animals， and we have evolved to be in groups. it found that those who had a large network of friends outlived those with the fewest friends by 22%.

　　情景對話1：

　　瑪麗打電話找湯姆，邀請他參加為吉姆舉行的驚喜生日晚會。

　　tom： （answering the phone）hello？

　�。ń与娫挘┪�？

　　mary： hello. may i speak to tom please？

　　喂，我找湯姆。

　　tom： speaking.

　　請講。

　　mary： hi， tom， this is mary. i'm a friend of jim's.

　　湯姆，我是瑪麗，吉姆的朋友。