Unit 21 In our class, most discussions and activities take place in assigned small groups. These groups provide a supportive and safe environment that promotes(促进) learning.在我们班，大多数的讨论和活动都在指定的小组中进行。这些团体提供支持和安全的环境，促进学习。2 It is the development strategy of the company to accelerate its overseas expansion in order to take a slice of the world market.为了在世界市场上分一杯羹，加快海外扩张是公司的发展战略。3 Nearly six million people go to see the Mona Lisa every year, attacted by the mystery (神秘)of her smile.When yo
