В введении авторы дали описание осн

В введении авторы дали описание основных проблем и их последствия в городе Шанхая.

Результаты (английский) 1:

In the introduction, the authors described the main problems and their effects in Shanghai.

Результаты (английский) 2:

In the introduction the authors have described the main problems and their impact on the city of Shanghai.

Результаты (английский) 3:

in the introduction, the authors give a description of the main problems and their implications in the city of shanghai.