英语翻译

问题描述:

英语翻译
POLLUTION IS ONE MOST SERIOUS ______(PROBLEM) IN THE WORLD
KIM______(LOUD) HIS LIBRARY BOOK LAST WEEK ,HE COULDN"T FIND IT
解释为什么这么填

1. problems(one of + *+ 名词复数..表示其中最...之一)
2. lost(last week上周,用一般过去时, lose的过去式: lost丢失)