1.They ____ us since five o'clock this morning.

1.They ____ us since five o'clock this morning.
A.are helping B.have been helping C.have been helping D.have helping
2.I ____ the book the whole day ,yet I have't finished it.
A.have been reading B.have read C.am reading D.had been reading
3.Please come in.We ____ about your paper.
A.talk B.had been talking C.have been talking D.had been reading
4.Such natural resources as coal and petroleum ____.
A.gradually are exhausted B.are being gradually exhausted
C.have gradually exhausting D.have been exhausting gradually
5.It ____ almost every day so far this month.
A.is raining B.rained C.rains D.has been raining