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。 小题1:There are two hundred boys r_______ from seven to four in age. 小题2:Dr. Yuan Longping searched for a way to increase a rich h_______ without increasing the area of fields. 小题3:When Liu Xiang won the 110-metre hurdle race, he was s________ by the clicking cameras of the media. 小题4:You’d better b________ yourself or else you’ll be in deep trouble when Mr. Wang comes in. 小题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.