【单选题】某项目工程的某个施工段最乐观工作持续时间为9天,最悲观工作持续时间为19天,最可能持续时间为11天,则该施工段作业所需时间为
【简答题】用所给动词的正确形式填空。 1. Did you see the accident this morning? (happen) 2. You should get a chair on. (sit) 3. There are so many children _________ (play) in the park on Sundays. 4. It's hot. You'd better bo...
【简答题】用所给动词的正确形式填空。 1. Did you see the accident ______ this morning? (happen) 2. You should get a chair ______on. (sit) 3. There are so many children ______ (play) in the park on Sundays. 4. It's hot. You'd...