要么因为信用证金额过大，要么因为对开证行不完全信任，出口商有时可能需要保兑的信用证。

要么因为信用证金额过大，要么因为对开证行不完全信任，出口商有时可能需要保兑的信用证。
【正确答案】：Sometimes the exporter may require a confirmed letter of credit either because the credit mount is too large, or because he does not fully trust the opening bank.