For Tom and other guys: About Dictioaries

Is it a good idea to begin using an intermediate dictionary until I can switch to an advanced one? I need your advice urgently. Thank you.

Get the Collins COBUILD Advanced Learner's dictionary, unless you find that it's absolutely too difficult for you -- which it shouldn't be, judging from your written English.

Yes, Collins Cobuild uses full sentences to explain. And it has ignored the taboo in dictionaries--the definitions contain the words themselves, which make the definitions good examples to show you how to use.

Good point -- it really was something of a taboo. Even the latest Cambridge Dictionary for Advanced Learners uses old-style definitions.