在电力系统潮流计算中，发电机节点的电压恒定，常作为PV节点，其幅值保持不变。当系统中某些负荷节点的无功负荷

The central idea of this passage is ______.

A．electronic transfer of funds

B．bank's payment mechanism

C．clearing of checks

D．computer and payment

“Shipment to be made subject to an advanced payment(or down payment)amounting×××to be remitted in favorof sellers by telegraphic transfer(or mail transfer)withindication of S/C No.XXX，and the remaining part oncollection basis，document will be released againstpayment at sight”，这是______与______相结合的结算方式。

“Shipment to be made subject to an advanced payment(or down payment)amounting×××to be remitted in favor of sellers by telegraphic transfer(or mail transfer)with indication of s／C No．XXX，and the remaining part on collection basis，document will be released against payment at sight”，这是_______与_______相结合的结算方式。

A．warning

B．transfer

C．charge

D．emergency

A、payment

B、Cross-border payment

C、transaction

D、logistics