Hello
 

I have a couple of questions regarding some translations. unfortunately.

for example, what about the sentence :
"he was obviously very unhappy. we were wondering what could possibly went wrong. " is it grammatically correct?

thanks in advance.

Re: Hello
 

No. After modal verbs - here could - you need an infinitive. In this case it's a past event so you need the perfect infinitive : have+ past participle.

So the correct sentence would be : We were wondering what could have possibly gone wrong or We were wondering what could possibly have gone wrong - I prefer the second, but both are acceptable.

Re: Hello
 

thank you!! I was even wondering at the possible use of had + past participle. but of course that doesn't exist