If a sum called in respect of a share is not paid before or on the day appointed for payment thereof, the person from whom the sum is due shall pay interest upon the sum at the rate of eight percent per annum from the day appointed for the payment thereof to the time of the actual payment, but the Directors shall be at liberty to waive payment of that interest wholly or in part.
本句的句子结构比较简单，为if引导的条件从句加上but连接的转折句。需要讲解的主要有以下几点：
1.Call
Call 在这里指的既不是“召集”，也不是“打电话”，而是“催缴股款”的意思：（公司法）催缴股款（通知书） 公司要求已认购股份但分期付款的股东交付股款，或者公司
要求已分到新发行股票但股款尚未全部交齐的股东交付股款【元照英美法词典】。
2.Payment thereof
这里的there指代的就是前面的sum, payment of sum，支付股款
3.Due
Due，"票据到期，期满应付"，表示债务或其他权利请求已到期并具有执行力，如：
Any mortgage, pledge, transfer of a security interest in, or lien, created by any Group Company, with respect to any of its material properties or assets, except liens for taxes that not yet become due or payable and liens that arise in the ordinary course of business anddo not materially impair such Company’s ownership or use of such property orassets
未曾有任何集团公司创设，与其任何重大财产或资产相关的，任何按揭、质押、转让或担保权益，或者留置；为尚未到期或应付的税款进行的留置以及在正常经营过程中产生的留置，且不会对该公司拥有或使用该等财产或资产产生重大影响的除外
4.Be at liberty to
Be at liberty to, 有权做某事
Should the Vessel be within any such place as aforesaid which only becomes dangerous, or may become dangerous, after her entry into it, she shall be at liberty to leave it.
万一船舶处于前述地点，但该地点在进入后变得危险或可能变得危险，则船舶有权自由离开。
