Gianmarco Ottaviano and Giovanni Peri point out that immigration
A．is immune from negative effects.
B．has lead to economic prosperity and social stability.
C．has enhanced wages of most American workers.
D．will root out illegal documentation of workers.

判断题三十六字母大约反映了先秦时期的声母系统。()

未分类题The plan of creating a new class of 'guest workers'A．has aroused criticism from conservatives, liberals and the business world.B．has allowed immigrants to work in the U.S. for six consecutive years.C．will benefit both businesses and immigrant labor employers.D．will give people a good reason to threat such workers as slaves.

未分类题What is the authors attitude towards guest workers plan?

未分类题Dr Maddux and Dr Galinsky adopted statistical controls toA．filter out the interference factors such as personality traits.B．identify the statistical relationship between personality and creativity.C．analyze the interaction between personality and creativity.D．measure the influence of openness to new experiences on creativity.

未分类题It can be inferred from Paragraph 4 that in Africa and AsiaA．the private sector is the last straw for health services.B．the physical condition of workforce is rather weak.C．some miners might have been infected with AIDS.D．HSBC attracts customers with innovative health schemes.