very effective
Ça ne paraît pas, mais c'est très efficace.
It may not look like it, but it's very effective.
— Akira (1988)
It is very effective.
Un boycott national est très efficace !
A national boycott is very effective!
— The Legend of Bhagat Singh (2002)
You are very efficient.
It was very effective.
Le suivi psychologique peut s'avérer très efficace.
Psychological support can be very effective.
Ce médicament est très efficace.
This medicine is very effective.
Ces étudiants travaillent dur, mais ce n'est pas très efficace.
These students work hard, but it's not very effective.
Mais quand c'est utilisé convenablement c'est très efficace.
But when it’s used properly, it’s very effective.
— Les 3 Royaumes (2008)