阅读理解。 Read the passage carefully. Then answer the questions or complete the statements in the fewest possible words. When the Internet powerhouse Yahoo wanted to teach ethics (道德标准) to its employees, it faced a challenge familiar to multinational companies. Yahoo employs nearly 14,000 people at 25 sites worldwide. They would feel bored at sitting down in front of a dated video in which actors with 1980s haircuts tell them what to do. So it hired a company calledThe Network $amp; where Yahoo was founded traveled the world, turning into a boat and a helicopter along the way as it visited some of Yahoo's foreign offices. Participants play in game show-like scenarios (场景) that quiz them about conflicts of interest and doing business fairly. And employees note: Yahoo is tracking how well they do. Such activities draw more enthusiastic participation and teach more effectively than traditional methods. They are described as alternative-reality games (ARGs), involving both interactive and real-world elements. Besides teaching employees, ARGs have also been used in many areas for a number of different purposes. From a marketing perspective, a number of very successful ARGs have been written as a way to build product awareness. A very popular ARG called I Love Bees was produced to market the 2004 video game Halo 2 $amp; I Love Bees received between two to three million unique visitors over the course of three months. ARGs are more than just a fun way to learn. They have also been used to solve real world problems. An ARG called World Without Oil $amp; was created to obtain collective input from players about dealing with the world's dependency on oil. World without Oil simulates(模拟) the first 32 days of a global oil crisis and anybody could play by creating a personal story that recorded the imagined reality of their life in the crisis. World Without Oil 's success on a small budget has opened the door for similar games to engage mainstream Internet users with climate change, education reform, governmental policy and other timely, vital issues. (Note: Answer the questions or complete the statements in NO MORE THAN TEN WORDS.) 1.What challenge did yahoo face in teaching ethics to its employees? 2.In the game designed for yahoo, participants had to answer questions about ________. 3.What are the three major functions of ARG mentioned in the passage? 4.The success of World Without Oil $amp; suggests that ARGs can __ ______.