Hello !!
I've a problem for my exercise ....You can help me ??
Complet using the right tense (simple past or present perfect ).
The problem of pollution .....(exist) for many years in our area . It approximately ....(start) in the sixties . Since then , people ...(take) a lot of measures but the results have been insufficient . In 1975 , when the explosion ...(happen) in the factory , everybody ....(agree) that something ..(have to) be done . I think that we ....(see) too many catastrophes: the government ....(not/promote) enough protection aver the past years . So far, we can consider that the autorities ...(not/do) anything really serious about the problems .They ...(make) too many promises in the past , now they must act !
....I'm not sure of my answer but I think is : has existed , started , took , happened , agreed , has to , have seen , haven't promoted , didn't , made ..
Thank you for advance..
(sorry for my english !!)