语法填空（本题有10题；每小题1分，共计10分）
阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词的适当形式填空。
Every society has its special words, expressions and ways of saying things. One of the popular expressions in the United States is “Hitting the books”. It__________ studying a subject with great effort(努力).
One of the great challenges for students _______(be) taking tests. Students spend long hours________ (prepare)  for a test. They read all their books carefully, and then read them a ____ time and a third time. They prepare for every possible question. They study every night. They are “hitting the books.”
In the United States, most children go to school ________ they are five years old. Public education is free and most children go to schools near their homes. School in these early years is fun. Children learn to read and write, but they also play games and go on trips. There is no reason _________ such an early age for them to hit the books.
This situation changes as children become older. The subjects become ________ ( difficult). Students must learn _______ world history, algebra(代数) and life sciences. Tests become more common.
Pressure _______ (grow) to hit the books, study hard, and advance(升级). ________, most students only really begin hitting the books for long hours when they reach high school.
Knowledge is a prize that is not easy to gain.