题干
Alice left the company half a month ago. Her work______unfinished since.
A：has left
B：was left
C：is leaving
D：has been left
答案(点此获取答案解析）
D
A：has left
B：was left
C：is leaving
D：has been left
＝a，
＝b，
＝4
，P为AD的中点，则
＝( )
