请问这句话的结构和用法

题目

请问这句话的结构和用法
摘自9月8号的BBC NEWS
Libya's National Transitional Council says it's sending a delegation to Niger to ask them not to give refuge to Colonel Gaddafi,should he try to enter the country,or any of his associates who've crossed the border in the past few days.
这句话的结构是啥,我主要不是很了解should前置的意义和用法,

答案

Libya's National Transitional Council says 利比亚过度委员会说,这是主句
it's sending a delegation to Niger to ask them not to give refuge to Colonel Gaddafi,should he try to enter the country,or any of his associates who've crossed the border in the past few days.这是说的内容,整体是宾语从句.内部的话,是一个对将来事实的虚拟,if引导的条件状语从句,省略了if,就要半倒装了.原句是it's sending a delegation to Niger to ask them not to give refuge to Colonel Gaddafi,if he should try to enter the country,or any of his associates who've crossed the border in the past few days.
should之所以前置是因为if省略,句子半倒装的缘故.
有什么疑问还可以问我,我一直在线.