请英语高手帮改一下语法错误

First of all, the topic sentence doesn't define exactly what the speaker is going to say, i.e. the advantages and disadvantages of using mobile phones and the functions of mobile phones. Also the first sentence in the passage is too simple for a sentence at the beginning of the topic and it repeats "business" twice. The speaker has used different forms of the words in the second sentence, which is not allowed in the essay except for quotation, and the third sentence is totally irrelevant. The part which starts at "It includes" and ends at "higher price" doesn't clarify the points of view the speaker wants to say. It doesn't make sense at all and the sentence which includes the quotation doesn't say the name of the author in reference. But the most important is that the whole paragraph doesn't demonstrate well enough. It doesn't show clearly what the advantages and disadvantages of mobile phones are just like the topic sentence.<