Doom means to impose a punishment on someone. It is always used in a negative way. He was doomed to life in prison for the murder he did. A book might say "he was doomed to hell" for the evil life he lived. A PERSON is always doomed, not a result or object. It can not be used as you have suggested, not preparing for a test. You would say that this way: "Because he prepared enough for this test, he will surely succeed in this test", or "He will do well in this test because he studied and prepared well."

Err... no, not like that. First, your sentence doesn't really make sense because of the shaky grammar. Also, "doom" is used for a negative and permanent consequence: "doomed to failure", or "doomed to a lifetime of regret". If you're not sure about word-order or collocations, try doing a search of whole phrases from your sentence - then you'll find examples of how it is naturally written.

Example: "I will doom you to a lifetime of slavery", said the Wizard.

Hello Panjianjin, when I think about this question, I realize that I can't think of any examples where "doom" is used in the active voice. Everything I come up with is in the passive voice. If anybody can think of any active voice applications of "doom," I would like to see them. Richard