I have _____ an eye _____ you now, so you do as you _____!

A．left; over; have to

B．to keep; on; were told

C．kept; down; have been told

D．kept; on; are told

二项分布接近泊松分布的条件是（）

A.μ=nπ

B.μ≥20

C.μ=0.5

D.n很大且π接近0

E.n很大且π接近0.5