Fill in the blanks with the given words in their proper forms. (用括号内所给单词的适当形式填空，

每空限填一词。)

1．We all know that Tom's mother is a very _________ business woman. (succeed)

2．A car accident happened in our street last night. _________, no one was injured. (luck)

3．My sister _________ fish in that market early every morning. (sales)

4．It's _________ for her to get school so late because she is always the first one to get to school. (usual)

5．Suddenly, we heard a big ________ in the next meeting hall. (argue)

6．In some maths tests, the students are allowed to use the _________ calculators. (electric)