起重机操作员需要经过严格培训才能上岗。

Crane ___operators must undergo rigorous training before they can work.

几家电信运营商正在合作改善农村地区的网络覆盖。

Several telecom ___operators are working together to improve network coverage in rural areas.

电信运营商正在升级网络系统。

The telecom ___operators are upgrading the network systems.

在这个数学表达式中，乘号和除号是基本的运算符。

In this mathematical expression, the multiplication and division signs are basic ___operators.