In a country that defines itself" by ideals, not by shared blood, who should be allowed to work and live here In the wake of the Sept. 11 attacks these questions have never seemed more pressing.
On Dec. 11, 2001, as part of the effort to increase homeland security, federal and local authorities in 14 states staged " Operation Safe Travel"—raids on airports to arrest employees with false identification. In Salt Lake City there were 69 arrests. But those captured were anything but terrorists, most of them illegal immigrants from Central or South American. Authorities said the undocumented worker’s illegal status made them open to blank mall by terrorists. Many immigrants in Salt Lake City were angered by the arrests and said they felt as if they were being treated like disposable goods. Mayor Anderson said those feelings were justified to a certain extent. "We’re saying we want you to work in these places. We’re going to look the other way in terms of what our laws are, and then when it’s convenient for us, or when we can try to make a point in terms of national security, especially after Sept. 11, then you’re disposable. There are whole families being uprooted for all of the wrong reasons. " Anderson said.
If Sept. 11 had never happened, the airport workers would not have been arrested and could have gone on quietly living in America, probably indefinitely. Ana Castro, a manager at a Ben & Jerry’s ice cream shop at the airport, had been working 10 years with the same false Social Security card when she was arrested in the December airport raid. Now she and her family are living under the threat of deportation. Castro’s case is currently waiting to be settled. While she awaits the outcome, the government has granted her permission to work here and she has returned to her job at Ben & Jerry’s.
According to the author, the United States claims to be a nation .（）
A．composed of people having different values
B．encouraging individual pursuits
C．sharing common interests
D．founded on shared ideals
的砝码，放置在小车上，不挂小桶，调节斜木板倾角，使小车能匀速滑下；
的砝码放到小桶中，重复步骤（2），测出对应的加速度； 
及a的数据，作出
的图线； 
，截距
，取重力加速度
，则可知小桶的质量
=______________kg，小车质量
=______________kg。步骤（1）中调节木板倾角使小车能匀速滑下的目的是____________________________。判定小车作匀速运动的依据是____________________________。