"Everyone has put in a lot of effort to make the course successful." "Everyone has put in a lot of effort to make the course successful." Is this sentence correct? I don't think so. I think it should be changed to: a. "Everyone has put a lot of effort into making the course successful." b. "Everyone has put a lot of effort into making the course." c. "Everyone has made a lot of effort to make the course successful." (Actually, I think a is still a little odd.) Am I right? Besides, what does the course mean here? Thanks!