问题如下：
The notional principal of a swap is:
选项：
A.not exchanged in the case of an interest rate swap.
B.a fixed amount whenever it is matched with a loan.
C.equal to the amount owed by one swap party to the other.
解释：
A is correct. The notional principal of a swap is not exchanged in the case of an interest rate swap.
B is incorrect because an amortizing loan will be matched with a swap with a pre- specified declining (not fixed) notional principal that matches the loan balance.
C is incorrect because the notional principal is equal to the loan balance. Although the loan has an actual balance (the amount owed by the borrower to the creditor), the swap does not have such a balance owed by one swap party to the other.
想问下A选项怎么翻译？the national principal swap 不是交换利率的一种swap，这样翻译吗？我们视频不是说这种swap交换利率，本金保持和银行借款的本金一致这样吗?
