阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。
Today I’m here to tell you about the survival course I and all other scientists have to go through when we arrive in the Antarctic , and this is       they call field training .
The first day’s training was the construction of snow shelters . We       ( divide ) into three teams      four persons in each team . Each team went for a different type of shelter . The Canadian       ( choose ) the snow shelter type ; the New Zealanders dug through a pile of snow and we decided to dig a hole in the ground . We       ( foolish ) thought it would be the easiest . So we set to work and after      ( dig ) for a couple of hours , it was beautiful , deep and long     unfortunately far too wide .      else succeeded with their efforts but we had to announce    ( fail ) , for we couldn’t get enough snow     ( build ) a roof . So in the end all we had was a deep hole and that’s how we came to sleep outside at night in one of the coldest places in the world .