Так как я знал его около пяти лет,

Так как я знал его около пяти лет, я мог порекомендовать его как хорошего специалиста.

Результаты (английский) 1:

Since I knew him for about five years, I could recommend it as a good specialist.

Результаты (английский) 2:

Since I knew him for about five years, I would recommend it as a good specialist.

Результаты (английский) 3:

as i knew him for about five years, i would recommend it as a good specialist.