问题如下：
When, at the end of an accounting period, a revenue has been recognized in the financial statements but no billing has occurred and no cash has been received, the accrual is to:
选项：
A.unbilled (accrued) revenue, an asset.
B.deferred revenue, an asset.
C.unbilled (accrued) revenue, a liability.
解释：
A is correct.
When cash is to be received after revenue has been recognized but no billing has actually occurred, an unbilled (accrued) revenue is recorded. Such accruals would usually occur when an accounting period ends prior to a company billing its customer. This type of accrual can be contrasted with a simple credit sale, which is reflected as an increase in revenue and an increase in accounts receivable. No accrual is necessary.
解析：收入已确认，但是还没有开票，企业会在资产中确认一个unbilled revenue，开票后，unbilled revenue（资产）减少，同时应收账款增加。如果再收到现金，就是应收减少，现金增加。
unbilled Revenue 和 differ Revenue 啥区别？
