浇筑混凝土作业时，模板仓内照明用电必须使用多少伏低压电？

The_ (month) salary for the position will be negotiable at around $2,000.

蛙式夯一人操作行吗？

向搅拌机料斗内倒水泥时，脚能否蹬在料斗上？

His mother becomes disappointed whenever he fails to live up to her________(expect)

拆墙时严禁挖、掏墙根，能否用人工晃动的方法推倒墙体？

It will be interesting to see what’s going to happen at the next________(elect).

在数字信号脉冲编码方案中，全宽码又称为不归零码，包括___和双极性不归零码两种。

Robots, ___(become) increasingly prevalent in factories and industrial plants throughout the developed world, are programmed and engineered to perform industrial tasks without human intervention.

混凝土坝的变形和应力的影响因素主要为自重、（）、温度及（）等四类。