阅读下列句子，根据所给开首字母，写出符合句子意思的本学期所学单词，注意必要的形式变化。 1. There are two hundred boys r_______ from seven to fourteen in age. 2. Dr. Yuan Longping searched for a way to increase a rich h_______ without increasing the area of fields. 3. When Liu Xiang won the 110-metre hurdle race, he was s________ by the clicking cameras of the media. 4. You'd better b________ yourself or else you'll be in deep trouble when Mr. Wang comes in. 5. The Spring Festival Gala has developed into an occasion that most Chinese find it hard to ignore, and millions of v________ are watching the performance being broadcast live.