Illegal aliens are people living in the U.S.A with proper__1__ authorization. Many entered the country by sneaking across the border. Others came on temporary student or visitor visas and did not leave until their visas were expired.__2__ Most illegal aliens want to stay in the U.S.A. because employment opportunities are so much great than in their native country. Since illegal aliens try hard not to be discovered by the government, it is possible to get an __3__ accurate count of them. Recent estimates ranged from __4__ 2.5 million to as high as 12 million. In 1986, the United States government adopted a new law affected illegal aliens— __5__ the Immigration Refrom and Control Act. This law was designed to accomplish two main goals:1) to allow illegal aliens who have been living in the country since __6__ January, 1982 to gain legal status if they applied by May 4,1988; and 2) to encourage others from coming into or __7__ staying in the country illegally by making difficult for__8__ undocumented people to find employment. The law prohibits American employers from hiring illegals and providing for severe penalties—fines and even imprisonment—__9__ if they do so. This new law has helped large number of__10__ formerly illegal aliens to become legal residents. But it also forces employers to check on all prospective employees who look or sound foreign to be sure that they have documents allowing them to work. This may discourage some employers from hiring any immigrants.
答案
1. with—without。根据illegal aliens的定义，应该是people living in the U.S.A without proper authorization
2. until—when。从逻辑意义上来分析，是Others....did not leave when their visas were expired（当签证到期时他们也不离开美国）
3. possible—impossible。从上下文的说明判断，要弄清楚到底有多少非法居住在美国的外国人，或得一个确切的数据是完全不可能的
4. ranged之前加have。因为是指did not leave until their visas were expired. Recent estimates而不是以往的estimates
5. affected—affecting。此处相当于（a new law）which/that affect illegal aliens
6. have—had。用过去完成时，因为整个句子讨论的是过去的事，并且此处具体指country since January, 1982 to gain legal status if they applied by May 4,1988
7. encourage—discourage。如果为encourage则与全文的逻辑和意义矛盾
8. 在difficult之前加it。making it difficult for undocumented people to find employment，其中it为形式宾语，实际宾语为不定式短语（for undocumented people）to find employment
9. providing—provides。provides for severe penalties与prohibits American employers from hiring illegals 为并列谓语，而不是与hiring illegals并列
10. number—numbers或在large之前加a。习惯为numbers of或a number of
责任编辑：wangpeng6151
