Who can help me to differentiate the accounting terms?

In accrual basis accounting, accrued expense is a liability resulting from an expense for which no invoice or other official document is available yet. Similarly, accrued revenue is an asset resulting from a revenue for which no official document was issued yet. The other side of the entry will always be a profit and loss account - expense in the first case and revenue in the latter one.
Example
Consider a company that is making an accounting close on the last day of December. During the closing works, they realize that they still have not received an invoice for telephone calls made during December, as the invoice is usually issued several days after month-end. However, they are able to determine the expected amount which will be invoiced. Because the calls were made in that year, the liability exists already at the end of December. As such, the company needs to record an accrual - a liability that exists, but for which no official document is available yet.
In this example, the accrual will be included as part of the journal entry. In this example, the journal entry will be: Debit Operating Expense / Credit Accruals. In accounting this is considered accrual basis accounting.
Deferred, in accounting, is any account where the asset or liability is not realized until a future date, e.g. annuities, charges, taxes, income, etc. The deferred item may be carried, dependent on type of deferral, as either an asset or liability.
Deferral in accounting
The term deferral is most commonly used in accounting as an abbreviation of deferred income (called also deferred revenue) or deferred expense (called also prepaid expense or prepayment).
Deferred income is a liability. It is recorded when an asset (e.g. receivable) is recorded, but the related income (i.e. revenue) will be earned only in the future.
Deferred expense is an asset. It is recorded when a liability is recorded, but the related expense will be incurred only in the future.
Example: Company A rents its building to Company B, which has its office in the building. Before the year ending 31 December 2005, the company A issues an invoice to company B. The invoice covers rent for two years: 1 January 2005 to 31 December 2006.
Total rent for the two years is 1,000.
Accounting in Company A as of 31 December 2005

Debit Accounts Receivable 1,000
Credit Income 500 (rent for 2005)
Credit Deferred income 500 (rent for 2006)


Accounting in Company B as of 31 December 2005:

Debit Rental expense 500 (rent for 2005)
Debit Deferred expense 500 (rent for 2006)
Credit Accounts payable 1,000

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