句型转换。

1. My mother got them yesterday from the post office.(改为一般疑问句)

    _____ your mother _____ them yesterday from the post office?

2. I think they would come tonight. (改为否定句)

    I _____ think they _____come tonight.

3. They are making birthday cards for Brian.(对划线部分提问)

    What _____they _____for Brain?

4. My group's favorite subject is physical education. (对划线部分提问)

    ______ favorite subject ______physical education?

5. We have lived in this neighborhood for two years. (对划线部分提问)

    ______ ______have you lived in this neighborhood?

在完全竞争市场上，厂商短期均衡的条件是（）。

A.MR=SAC

B.MR=STC

C.MR=SMC

D.AR=MC