be supposed to do简单

PreCheck is supposed to be a win-win for travelers and the TSA.

“预检”项目本应让旅客和运输安全管理局实现双赢。

Researchers measured people’s cortisol, which is a stress marker, while they were at work and while they were at home and found it higher at what is supposed to be a place of refuge.

研究人员测量了人们在工作时和在家时的皮质醇（一种压力指标），发现在本应是避风港的地方，皮质醇水平反而更高。

At work, people pretty much know what they’re supposed to be doing: working, making money, doing the tasks they have to do in order to draw an income.

在工作中，人们基本清楚自己应该做什么：工作、赚钱、完成为获得收入而必须做的任务。

Outside directors are supposed to serve as helpful, yet less biased, advisers on a firm's board.

外部董事理应在公司董事会中充当有益且较少偏见的顾问。

We learn from Paragraph 2 that outside directors are supposed to be ____

从第二段可知，外部董事理应是____