How to know which one is clause or sub-section

Please note that the main section consists only of numbers & the sub-section, clause & the sub-clause consists of alpha-numeric numbers.  This is explained as below. 

There is an section in the Income-Tax named 10(23C)(iii)(ae) relating to exemption of Income for hospitals.  Following is the explanation:

10- It is the main section of the IT Act

23C- It is the sub-section  of section 10

iii- It is the sub-clause of sub-section 23C

ae- This is again the sub-clause of the sub-clause iii

Hope the above would clarify your doubt

hello friends !

can any one explain me in detail about how read secction, subsection,clause and rule 

in tax laws.

They are read simply but for official purposes/better impression in papers written backwards in statements.

For example -

10(23C)(iii)(ae) would be 

Read as Section 10 ,  Sub section 23C , clause iii , sub clause ae

Written as (for better presentation wise , not compulsory for exams) - As per sub clause ae of clause iii of Sub section 23C of Section 10 ....