一、下面每句都有一个标点符号错误，该用标点处未用标点或标点符号用错，改正错误或补写标点。

1.I doubt that he can answer your question

2.In short employees must work hard and creatively.

3.We are considering Boise,Idaho or Phoenix Arizona as a possible site for our factory.

4.Everybody knows that,we have a very challenging sales quota to fulfill this year.

5.The aircraft exhibition will be open seven days a week from 9 am to 6 p.m.

答：1.dispensable→indispensable 

2.Comparing→Compared

3.is become→is becoming/has become 

4.fluent→fluently

5.do→doing