It is a safety procedure in industries that lock dangerous machines and ensure that there is no operation until maintenance or repairs have been made.
Answer:
I'm not sure if you have any options or what you really need here. but i can tell you that this sentence is not correct.
Explanation:
The word which should be changed is affect. The word affect can only be used as a verb to affect and not as a noun. It should be changed to effect here. It had a strong EFFECT on my life.
Answer:
A struggle between the Eastern Bloc and the West that lasted 40 years.
It's not A or B. And between C and D, I'd choose flexible schedules. <span />