16．In the United States，"hitting the books"means studying a subject with great effort．
One of the great challenges for students （36）B taking tests．Students （37）C long hours preparing for a test．They read all their books carefully，and then read them （38）B and a third time．They prepare for （39）D possible question．They study every night．They are"hitting the books"
In the United States，most children go to school （40）A they are five years old．Public education is free and most children go to schools near their homes．School in these early years is （41）C．The children learn to read and write，but they also play games and go on trips．There is no reason （42）A such an early age for them to hit the books．
This situation changes as children become older．The subjects become more difficult．Students must（43）Bworld history，algebra（代数）and the life sciences．Tests become more common．
Pressure （44）Ato hit the books，study hard，and advance（升级）（45）D，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．
| 36．A．are | B．is | C．were | D．was |
| 37．A．cost | B．take | C．spend | D．pay |
| 38．A．a first | B．a second time | C．a third time | D．a fourth time |
| 39．A．all | B．no | C．few | D．every |
| 40．A．when | B．since | C．for | D．that |
| 41．A．boring | B．difficult | C．fun | D．strange |
| 42．A．at | B．on | C．in | D．for |
| 43．A．look for | B．learn about | C．set up | D．hear of |
| 44．A．is growing | B．is disappearing | C．is falling | D．is going |
| 45．A．Although | B．Even | C．Whatever | D．However |
