用方框内所给词或短语的适当形式完成下列句子．（每词或短语限用一次，有一个为多余选项）

We      almost     allow      get   tooth       all over

47．Stonehenge， a rock circle in England， is believed to be　　 5000years old．

48． It's very important for us teenagers to learn how to take care of　　

49． We're going to do an English course in Britain next week， so we　　 things ready now．

50． Cola and candy are very sweet， and too much sugar is bad for your　　．

51． Some children like to buy food from shops outside school， but this　　．