2 Complete each sentence with the correct form of the present perfect or past simple.

2

• Mexico City (a)has sunk (sink) over 7 metres in the last 100 years because the city is built on an old lake.
• (b)has grown (grow) from about three million people to nearly nine million.
• which in 2018 (c)was (be) almost 21 million.
• Air pollution there (d)has got (get) a bit better in the last few years.
• In 2015, they (e)finished (finish) building the city's highest skyscraper.
• people (f)have studied (study) there, including Carlos Slim (one of the richest men in the world), Octavio Paz (Nobel Prize in Literature), and at least six presidents of Mexico.
• campus (g)became (become) a UNESCO World Heritage site in 2007.
• (h)has helped (help) people to move around the city more easily since it opened around 1969.