What tense should "gather" be changed to in the sentence about rain clouds?

In the context of the sentence about rain clouds, changing "gather" to "gathered" is appropriate if the sentence describes a completed action or event. The past tense form "gathered" indicates that the rain clouds have already amassed, which aligns with an overall narrative that reflects on events that have occurred.

This use of the past tense helps to convey a clear timeline in the writing. If the sentence is meant to describe a situation that has already taken place, such as when the rain clouds formed before a certain point in time, then "gathered" emphasizes that completion.

Other forms, such as "gathering" (the present participle) or "gathers" (the present tense), suggest ongoing action or habitual action, which might not fit the intended meaning of the sentence if it is focusing on past events. Thus, "gathered" is the correct choice for accurately reflecting the time frame and context regarding the rain clouds.