"he who sings, prays twice". what does st augustine mean by this statement?

1. Perhaps it is that when they sing a hymn or a song they pray with words as they sing aloud and and they pray with the heart as they hear the words they have just sung.

2. Perhaps it is that the words they sing are more memorable than the words they speak, so they tend to sing them to themselves afterwards and thus repeat the prayer.

Perhaps it means something else - but its haunting and elusive profundity reminds them that music, and singing in particular, has been a central feature of much Christian worship.

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.

the correct answer is “opportunity cost”. opportunity cost is what a company misses out because it decided in one option over another one. in this case, the company decided to invest in building a factory so it gave up another possible benefit or profit in order to achieve success with the factory.  

trade-off is not the correct answer since it is a situation in which you accept losing something in return for benefits in other areas.

and finally, consequence is a general term used to accept what it comes when you make a decision. it can be a positive or negative consequence depending if the decision you took was the correct one.