同学你好，该知识点来自沪江网校《大学水平直达CATTI三级(笔译+口译）【随到随学班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学好
主句为“An upgraded customs system was not ready for March or April, but will now be partly in place by October.”
中间的“needed to handle the large number of customs declarations that will have to be made once tariffs are in place”是插入语。其中，“that will have to be made once tariffs are in place”是定语从句，修饰customs declarations；once tariffs are in place是状语。
翻译时可以先翻译“处理大量海关申报”，翻译主句时增添代词“它”作为后半句的主语哦~
希望对同学有帮助，祝学习进步！