Both sentences are perfectly correct and frequently used by educated native speakers. The second one is either passive voice or simply an adjective predicate describing a past condition. The first one is an example of “middle voice”, a linguistics term that you can look up in the reference source of your choice, or go to the Wikipedia article: https://en.wikipedia.org/wiki/Voice_(grammar)#Middle_voice

Hi Laura, the second one is absolutely correct!

I'll add to what Thandolwethu said, the second one seems more correct to me because prequalification is part of a decision making process. Someone else prequalified them, we're using the passive voice because it isn't important right now WHO prequalified them, just that they WERE prequalified. So, the committee deciding who would get to host the national laboratory looked at these 100 companies and said "these look pretty good, we'll come back later to give them extra attention."

第一个句子是错的，因为没有谓语，第二个句子是正确的。

Thanks so much Nathan, it seems I can understand what you said a little bit. But I wanna know if the first one is correct in grammar?