1.【答案】B。
解析：The opening balance on the ledger is $15,000 CR, this is the amount that would have appeared in the trial balance at 1 July 20X4. 应付账款的会计分录是贷增借减，一般来说期末是贷方余额，结转至下期期初也是贷方余额(注意时间点)。
知识点：Ledger accounts, debits and credits
2.【答案】A。
解析：Discounts allowed are recorded in the cash book. Credit notes received are to do with returned purchases (not sales). Trade discounts are not recorded, as they are deducted on the sales invoices and only the net sale is recorded. Sales day book记录的是赊销。商业折扣与赊销还是现金销售无关;收到上月赊销商品的现金应该记录在现金日记账簿中;销售方赊销商品(服务)时开具发票，起到催收的作用;Credit notes是供应商开具的关于确认客户退货或退款的单据。
知识点：The need for books of prime entry
