I suggest you write it down and some people here will revise for you . This is the feasible way to learn a far complex sentence step by step .

A complex sentence is one containing one main or independent clause (also called the principal proposition or clause), and one or more subordinate or dependent clauses.

Sorry to sound harsh, but a sentence will always be wrong if you don't use capital letters and punctuation properly. To structure a sentence with relative clauses, the relative clause (ie. extra information about a thing) immediately follows the thing it describes. If the extra information is vital, then you don't use commas. If the information can be cut out without affecting the rest of the sentence, then you use commas. There are many more rules to writing complex sentences, but getting relative clauses right is a good start.

thanks you for detail knowlegde details.i got it.these details made me more clearly.could u show me what are the difference between complex sentences and compound-complex sentences for me?i always misunderstand two kind of sentences.

I will be glad to share more with you if you like. Some of the problems I have seen when students of English first attempt complex sentences, is the excessive uses of commas, in which statement after statement is written, when the paragraph could be more effective if brief individual sentences were used. Complex sentences are usually the art of a more advanced writer. Badly composed, they can present a nightmare of confusing verbiage. Deftly done, the complex sentence can bring clarity to the expressions of ideas that are not so simple. . --Warm Regards, Bruce .