管用 (guǎn yòng): efficacious; useful

I caught a cold and drank a bowl of ginger soup. To my surprise, it really worked—by the next day my nose had cleared up.

This phone's battery is getting worse and worse; even after charging all night, it only lasts a few hours.

The child refused to eat, and no matter how his grandmother tried to persuade him, it didn't work. In the end, it was his mother who came up with a solution.

If you want to improve your spoken Chinese, just memorizing vocabulary won't help much; you also need to chat more with Chinese friends.

He has tried many ways to lose weight—running, dieting—but what works best is simply eating fewer sweets.

The doctor said this medicine is very effective for headaches, but you can't take more than three tablets a day.