I (just) woke up ( from a nap) . I ( pronoun)<-----------------always use a capital letter.
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i want to buy mobile phone
我想買部手機
I<---------- capital letter
mobile phone( British) cellular phone cell phone( American)
phone <-------- is a countable noun. When you talk about " one", you have to use " a" or just " one".
I want to buy ( purchase) a mobile phone.
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she wants to buy news paper
她想買報紙
She<------------------------ capitalize the first word of the sentence.
newspaper/ paper = 報紙 paper can mean 報紙 too.
She wants to buy a newspaper/paper. a newspaper or a paper
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他有冇手機 <-------THIS IS A QUESTION!
he have mobile phone <------ not a question here!
Does he have/own a mobile phone? = 他有冇手機= A QUESTION
or
Does he have any mobile phone?
In present tense, he/she/it ------------- does in questions
Does he like ( verb) me?
Does she love( verb) me?
Does it matter( verb)?
then
Does he HAVE( verb) a car ?
You don't have to change the verb " have" here.