单选题

The author’s attitude towards “Diasporas” is that _____.

A There is increasing hostility towards immigrants in rich countries.

B Immigrant networks are a rare bright spark in the world economy and rich countries should welcome them.

C The Diasporas should return to their homelands so that poor countries will not suffer as a result of “brain drain”.

D Hard-working immigrants will depress the wages of the locals although they may greatly increase productivity.

解析：
文章多处提到移民为世界经济发展做出贡献。例如第六段提到在富裕国家的“Migrants”不仅“send cash to their families”；他们还会帮助公司“operate in their home country.”不仅如此，倒数第二段提到了移民为富裕国家也做出的贡献。最后一段也提到“Rich countries”将会从宽松的移民政策中获益。因此B项指出移民是世界经济中难得一见的亮点，富裕国家应该欢迎他们是符合作者对“diasporas”的态度的。A选项是一个事实，不是作者态度。因此不选A。文章最后一段“The prospect of working abroad spurs more people to acquire valuable skills, and not all subsequently emigrate”说明有些人只是到国外学习，并不移民；另外一些人才会回国开公司，因此担心不发达国家会“brain drain”是过分夸张的，故C选项错误。从文章第七段可以看出的确有一些研究表明来自“unskilled immigration”的竞争会压低“unskilled locals”的工资，但是其他研究发现，这种影响“to be small”或者“non-existent”，因此D项错误。