Experiments have already been done in this field, but only on a small scale.

该领域的实验已在进行，但是仅是小规模地进行。

youdao

Experiments have already keen carried out in this field.

实验已经激烈进行这方面的工作。

youdao

Experiments have already keen carried out in this field.

实验已经激烈进行这方面的工作。

youdao