A truly [систематический] approach will soon spot the error.

methodical

Info: The form “methodic” is understandable, but extremely rare.

Several [предположений, гипотез] turned out to be untenable.

Hint: Note that this is an irregular plural!

hypotheses

That was hardly a very [подходящий] response!

appropriate suitable fitting proper fit

The little [община] was located in a peaceful dale surrounded by forests.

community

Info: This is a more abstract term than “village, hamlet, town”.

The [концепция] of divide and conquer did not die out with the Romans.

Hint: Find a synonym for “principle”!

concept principle

This cell phone has some useful handicap-friendly [свойства] .

Hint: Find a synonym for “functions”!

features functions

Those in his immediate [окружении] soon noticed the difference.

environment vicinity proximity

Info: ”surroundings” or “area” don’t work with a social proximity.

We are [обязаны] by law to request your name and address.

Hint: Find a verb in the passive!

required obligated obliged