2 . The boy hid himself behind the tree __________ case his father could see him. (用适当的词填空)

3 . She began to cry the i________(一……就) she read the letter from her mother.

4 . It takes three hours, ______（无论哪个）route you take.

5 . The police set about arresting the suspect ________ moment they found enough evidence to prove him guilty. （用适当的词填空）

6 . W_______the old computer system is rather complicated, the new system is fairly simple.

7 . The difficulty which we had c_______ (交流) with the local people has now been removed.

8 . The gold medal will be awarded to w_____ wins the first place in the bicycle race.

9 . If we s_____________ a number for each letter, the message “Meet me” would read “135520135”.

10 . The study showed that a mere 5 to 10 minutes a day of running________(减少) the risk of heart disease and early deaths from all causes. (根据汉语提示单词拼写）