The mother of a 2-year-old child tells the nurse that her baby is using a potty seat but is still having problems toilet-training. Which of the following suggestions by the nurse would he most appropriate

A．Offer the child more praise each time.

B．Use a potty chair instead of a potty seat.

C．Focus on the "accidents" that occur during training.

D．Defer training until the child is developmentally ready.

各类型变压器损耗比较应考虑（）。

A.应估算变压器的损耗

B.优先选用高能耗的变压器

C.综合考虑变压器的运行成本

D.综合考虑变压器的设备投资