Some teachers have an ill impression of e-dictionary, which could be reasonable. However, it depends on the e-dictionaries they refer to. If the e-dictionaries only tell the user of the pronunciation and some concise Chinese definitions without any trace of collocations or sentence examples, they are, politely speaking, for emergency only. If you are a Chinese student in a hope to grasp English as a life-long communication tool, please choose your e-dictionary carefully. Someone argues that we’d better refer to the paper dictionaries. But how can we resist the temptation of turning to e-dictionaries which can hold every words of the paper ones while offering quick entries and cross-reference? Isn’t that over-stubborn to reject the convenience the modern science and technology bring about and be a paper-dictionary slave? We are not doing research. We are English learners for practical purpose.

Er… I’m not here advertising for any brand of e-dictionary, for I am here, you see, just talking about the my point of view of some wise choices you would probably make. And I hope that you can easily get the answer to the title question. Good luck!