1. This is the preferential treatment I enjoy as an American citizen.
    这还是我作为美国公民所享受到的优待呢。

2. A bill now before Congress would give preferential treatment to foreign students with advanced degrees in science and engineering who want to work in the United States.
    一份议案已递交到了国会，这一议案要求给予那些想在美国工作、具有理科和工程学科高级学位的外国留学生以优厚待遇。

3. In the first place, any scientific study requires that there be no preferential weighting of one or another of the items in the series it selects for its consideration.
    首先，任何科学研究都要求人们对可供考虑的诸多因素不能厚此薄彼，偏向某一方面。