根据括号中所给提示用定语从句完成下列句子

A student _who works hard and achieves high grads in exams___will earn respect from others.(you work hard and achieve high grads in exams.)

you may look up a dictionary_that has chinese definitions for english words___when learning new words from english articles.(the dictionary has chinese definitions for english words.)

The policeman _whom I am greeting now___was my uncle.(i greetes a policeman just now.)

Mr yang liwei's trip to outer space has realized the dream_that the Chinese people had dreamed for years___.(the chinese people had a ream to go to outer space for years.)