2.　　　　 He gave up a rich life for his ideas. (1-5英雄)

1.　　　　 He has given up many things in his life to help others. (1-5英雄)

8.　　　　 All countries can take part. (2-2奥运)

7.　　　　 take part in the Olympics (2-2奥运)

6.　　　　 He sang his latest hit and joined in. (2-5音乐)

5.　　　　 Women were not allowed to join in. (2-2奥运)

4.　　　　 Join in discussion(1-1朋友)

3.　　　　 Dao Wei will join us there. (1-3游记)

2.　　　　 The prison guards also joined us. (1-5英雄)

1.　　　　 I joined the ANC Youth League as soon as I could. (1-5英雄)