Можете объяснить, , расстановку артиклей в этих предложениях: 1)i managed to convince them that insurance is the very career path i intend to pursue. 2)little things like that make all the difference. 3)/cost of maintance can be considerable(перед cost). 4)we caught /sight of a small white dot on the horizon(перед sight ). 5)so some people were critical of the project because of the expense.

1) I managed to convince them that insurance is THE very career path I intend to pursue. усиление - "тот самый" и индивидуализирующее определение - 
"I intend to pursue".
2) Little things like that make all THE difference. имеется в виду известная разница.
3) Сost of maintance can be considerable. Абстрактное существительное в общем смысле.
4) We caught /sight of a small white dot on the horizon. Абстрактное существительное в общем смысле.
5) So some people were critical of the project because of THE expense. Не любые расходы, а расходы на этот проект (по ситуации известно, какие расходы).