The contract performance covers a 6 month base period with four one-year option periods.

合同日期包括6个月的基本期和四个为期一年的选择期。

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You will be seeing today new data that show why, over a 20-year period, every proposed option for controlling polio will cost more, in human suffering and dollars, than finishing eradication.

你们今天将看到新的数据，表明为什么提出的每项控制脊髓灰质炎方案在20年期间造成的人类痛苦和金钱方面的代价将高于完成根除工作所需的费用。

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The contract includes a base period of five years with one five-year option.

该合同包括一个5年的基本期和一个5年期选项。

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Mr Prowle also suggested a bailout from the government could be an option for an interim period while the trust "sorted itself out".

BBC: Sherwood Forest NHS trust debt increases by ?2m

The option ARM allows borrowers to pay less interest than the formal rate for a limited period (the vast majority of customers choose this option).

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One option is to reimpose capital controls for a temporary period (which would punish speculators but might reduce confidence in the financial markets).

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