机器传动部位运行时严禁做哪些工作？
参考答案：
严禁在机器传动部位运行时进行清扫注油和清理，不准隔着转动机械传递或拿取工具物品，禁止跨越皮带。
I noticed my little son ____ the words ____ on his small blackboard. [ ]
A. read; writing
B. reading; writing
C. to read; written
D. read; written
限性遗传（sex-limited inheritance）
