1 . It is believed that Chinese calligraphy d_________back to at least the Han Dynasty. (根据首字母提示单词拼写)

2 . They f______ all their attention on finding a solution to the problem. (根据首字母单词拼写)

3 . My mother didn’t a_____of me leaving school this year. （根据首字母单词拼写）

4 . The boy p_________ to be asleep when he heard the knock on the door. （根据首字母单词拼写）

5 . If you hide away your problems and pretend that they don't e___________, they will continue to mount up. (根据首字母单词拼写)

6 . The speaker r___________ to his notes several times during his speech. (根据首字母单词拼写)