单项选择题
A、1层 B、2层 C、3层 D、4层
A、DK-KK-RCD B、DK-RCD-KK C、KK-RCD-DK D、RCD-KK-DK
A、I△>30MA,T△=0.1S B、I△>30MA,T△=0.1S C、I△>300MA,T△=0.1S D、I△>300MA,T△>0.1S,I△·T△≯30MA·0.1S