1. situated   adjective   

原句: How many smaller structures could be situated very close together in order to generate as much power as you get from the very large ones.

意思: in a particular place or position 

例句: My bedroom was situated on the top floor of the house.

1. equation   noun   

原句: They can all be described by the same equations.

意思: a statement showing that two amounts or values are equal, for example 2x + y = 54

字源: late Middle English: from Latin aequatio(n-), from aequare ‘make equal’, from aequus ‘even, level, equal’. 

例句: This can be shown by a simple equation.