1、An increasing number of experts believe that migrants will exert positive effects on construction of city. However, this opinion is now being questioned by more and more city residents, who complain that the migrants have brought many serious problems like crime.

　　2、Many city residents complain that it is so few buses in their city that they have to spend much more time waiting for a bus, which is usually crowded with a large number of passengers.

　參考譯文：

　　1、越來越多的專家相信移民對城市的建設(shè)起到積極作用。然而，越來越多的城市居民卻懷疑這種說法，他們抱怨民工給城市帶來了許多嚴(yán)重的問題，比如犯罪。

　　2、許多市民抱怨城市的公交車太少，以至于他們要花很長時間等一輛公交車，而車上可能已滿載乘客。