Rashi on Genesis 29:6/רש"י על בראשית כ״ט:ו׳

1באה עם הצאן IS COMING WITH THE FLOCK — The accent in the word באה is on the א, and the Targum is אתיא (a participle), “she is coming”; but in (v. 9) “And Rachel came (באה)”, the accent is on the first syllable, on the ב, and the Targum is אתת, “she came”. The former expresses the meaning “she is doing something” (a participle), the latter expresses the meaning “she has done something’ (a past tense).