b 1 = TRIM(MID(SUBSTITUTE(SUBSTITUTE($ a 1，"("，REPT("，99))，")，REPT("，99*COLUMN(A 1)-98，99))

Array formula, after input, press CTRL+SHIFT+ ENTER in the edit bar at the same time, so that the formula is generated after {}.

Drag or copy to fill other blank cells.

Pay attention to whether the brackets () in your original data are full-width or half-width, and half-width is used in the formula.