效果不好可以怎么说英语

There are many ways you can express that something is not effective in English. Some options might include:

It's not working very well.
It's not producing the desired results.
It's not having the desired effect.
It's not effective.
It's not efficient.

You can also use more specific language to describe the specific issues or problems that you're experiencing. For example, you might say:

It's not achieving the expected outcome.
It's not meeting the desired criteria.
It's not reaching the desired performance level.

You can also use more colloquial or informal language to express this idea, such as:

It's not cutting it.
It's not doing the trick.
It's not getting the job done.

The specific language you choose will depend on the context and your audience, as well as your personal style and preferences.