Ⅰ.单词集训
A．词形转换
1．She now helps in a local hospital as a volunteer (voluntary) three days a week.
2．The developing countries need not only financial (finance) help, but also technical help.
3．China slowly develops a more reliable social security (secure) system for retirees.
4．He took the machine apart to show every detail of its operation (operate)．
5．People in that country used to use camels, oxen (ox) and
elephants to travel over land.
6．Political news is often related to economic (economy) and social problems.
7．Since 1976, he has been operating the shop with the assistance (assist) of volunteers.
8．He received a letter of thanks for his donation (donate) of $10,000 to charity.
9．As the capital of China, Beijing is the political (politics), economic and cultural center of the country.
10．Mailmen usually sort the mail at the post offices before distribution (distribute)．
