1.I never seen anyone run so fast----just watch David go.请帮我分析下破折号后的成分.

1.I never seen anyone run so fast----just watch David go.请帮我分析下破折号后的成分.
2.——with no way to reduce her pain and suffering from the terrible disease,the patient sought her doctor's help to end her life.
A.Having given up hope of cure B.With no hope for cure为什么选B,不用A?
3,___ and I'll get the work finished.
A.One more hour B.Given one more hour为什么选A,不选B?
4.The glass doors have taken the place of the wooden ones at the entrance,___in the natural light during the day.
A.to let B.leting为什么选B,不用A?
5.What are you thinking of ___ rid of the flies?
A.to get B.getting为什么选A,不选B?
6.I hear Warren ____ in a middle school.
A.teach B.teaches为什么选B,不用A?