在生态系统中，能把有机物变成无机物的生物成分是（  ）

A．只有生产者

B．只有消费者

C．只有分解者

D．生产者，消费者，分解者

—Isn't it a surprise that I happened to meet Francis Mafhews at the Christmas party last week?

—If my memory serves me correctly, you ____ each other for exactly two years. [ ]

A. hadn't seen

B. haven't seen

C. didn't see

D. don't see.