【单选题】

One of the many oddities of migration policy is that immigrants coming in to work permanently are usually a minority of those who arrive legally. Most (1) countries admit migrants mainly on grounds that have (2) to do with work. They also admit two large groups on grounds that have nothing to do with their skills or education, (3) these characteristics may determine (4) rapidly they integrate.

Almost everywhere, the biggest group (5) relatives of those who have already (6) . In the United States they (7) three-quarters of all legal (8) migrants.America even gives a few visas to (9) adult siblings. In parts ofBurope, family reunification has become family formation, (10) sometimes delays integration: for instance, it allows third-generation Pakistanis to seek spouses (11) their cousins back in rural areas. The policy also (12) the characteristics of earlier arrivals. (13) migrants are likely to have less educated relatives than are skilled migrants.
InEurope, and especially northernEurope, the other main route of legal entry is to claim asylum. The (14) of claims has fallen by half since the early 1990s, partly because peace (15) to former Yugoslavia, and partly because of tougher rules, (16) still seems to be higher than in the United States.America (17) the numbers sharply after the first attack on the World TradeCentre in 1993, mainly by refusing (18) asylum-seekers to work or draw any welfare benefits for the first six months of their stay, and by (19) the claims process. ManyEuropean countries (20) that way.
A、skillB、skilfulC、underskilledD、Unskilled