1 . Now the factory workers here have their temperature taken at i___of 4 hours. （根据首字母填空）

2 . Several red and white barriers marked the road at regular ________ (间隔) of about a mile. （根据汉语提示单词拼写）

3 . There will an i________ of 20 minutes after the second act of the play. （根据首字母单词拼写）

4 . There will be an i_________ of 20 minutes after the second act of the play. (根据首字母单词拼写)

5 . Remember we were talking about beat, which is the regular pulse, the pulse of life, the pulse of music, that comes at regular i____________. (根据首字母单词拼写)

6 . To protect our eyesight,we are supposed to have our eyes examined at regular_________（间隔）. (根据汉语提示单词拼写）

7 . Between the two parts of the concert is an i________, when the audience can buy ice-cream. (根据首字母单词拼写)

8 . To protect our eyesight,we are supposed to have our eyes examined at regular_________（间隔）.

9 . Early underground lines needed large holes leading to the surface with spaces in between — at regular i________ to get fresh air.