In 2003 it was ready for the people of St Petersburg when they.
问题描述：
In 2003 it was ready for the people of St Petersburg when they.
In 2003 it was ready for the people of St Petersburg when they celebrated the 300th birthday of their city.是什么从句?定语?状语?
答
when引导定语从句,先行词是in 2003,when这个句子是2003的定语