1.A lot of advice has been given by people on how to protect the environment. -- I removed 'that.' I would also consider removing 'by people.' It would be: A lot of advice has been given on how to protect the environment. If you leave in 'that', it would be a sentence fragment and would need a predicate: A lot of advice that has been given on how to protect the environment IS POORLY FOLLOWED. 2.What terrible weather we had yesterday. -- This would be like an exclamation of disbelief. What terrible weather we had yesterday! If you are stating a fact without that emotion: We had terrible weather yesterday. Hope that helps.

(American English) The first one should be either 1. A lot of advice HAS BEEN GIVEN by people on how to protect the environment. or 2. THERE'S a lot of advice that has been given by people on how to protect the environment. Which you choose depends on what you mean. -- Your final sentence should be "If they are wrong, please help me correct them." OR "If they are wrong, please correct them for me."

I think the first one is wrong.