1.Race____ (隔离) lasted about two centuries in America until the last half of 20^th century.　 1.____________

6.deserted　 7.mental　 　　　　8.merchant 　　9.Biology　 　10.delivered

10.Letters ____ (邮递) by air is much faster than those by train, but they cost more.　　　 　　　　10.____________

Keys:　 1.mercy 　2. entrance 　　　3. hesitation　 　4.national 　　5. attention

9. _____ (生物学) is the science of life and living things.　 　　　　　　　　　　　　　　　　9.____________

8. Mike , a foreign ______ (商人),came to our factory last week.　　　　 　　　　　　　　　　8.____________

7. Is the difference between manual (体力) and ______ (脑力) labor great in our country? 　　　　7.____________

6. He ____ (舍弃) his wife and children and went abroad.　　　　　　　 　　　　　　　　　　6.____________

5. The problems of the laid-off workers and re-employment has caught great social ____ (关注).　 　5.____________

4. There are two ____ (国家) languages in Canada.　　　　　　　　　 　　　　　　　　　　　4.____________

3. Without any　　　　　　　　 (犹豫), she took up the red flag and rushed out.　　　　　　　　　　 3.__________