to test the waters 试水，试行

英文释义

To experiment cautiously before proceeding (reference to touching hot water cautiously before bathing).

例句

No one was certain about the success of the clever new product, so it was introduced in a few stores just to test the waters before national distribution began.

对于这款灵巧的新产品能否成功，没人有把握，所以在开始全国分销之前，它先被送到几个商店里试卖。