开关量信号根据重要性可分为三类，其中不包括（）。
A.状态信号
B.状态信号
C.报警信号
D.告知信号
参考答案：A
During the reading lesson, the teacher asked students to read a few ______ from the novel.
A．pieces
B．essays
C．fragments
D．extracts
多核巨细胞(multinucleated giant cell)
