Sets B alongside A as the fixed reference, then states how A stands once the two are weighed; formal/written register.
框 · Frame
(A) 與 [B reference] 相比, [claim about A]
觸 · Trigger
You want to hold one thing fixed as a yardstick, in formal register, then say how the other stands against it.
序 · The move
1Name A, then open 與 and set down B — the fixed point you weigh A against.Is B the held-fixed backdrop, not the thing the remark is about? The remark lands on A.
2Close the bracket with 相比 and a comma.相 sits before 比, and a pause (comma) breaks the frame before the claim.
3After the comma, state how A stands.The claim sits outside the bracket; A is its subject, B never reappears in it.
例 · Examples
1這座城市this city現在now與with (formal)五年前five years ago相比weighed against, each against the other，繁榮了許多has grown far more prosperous。
Compared with five years ago, this city is now far more prosperous.
界 · Boundary
跟/和…比起來
Same framed comparison, different register and close. 與…相比 is written/formal and closes with 相比 (the looking turned both ways); 跟/和…比起來 is the everyday spoken frame and closes with 比起來 (起來 lifts the comparison into view). Swap registers and 與…相比 reads stiff in speech, 跟…比起來 reads loose in an essay.
A比B
A比B ranks two items on one bare quality in mid-sentence (弟弟比哥哥高). 與…相比 wraps B in a fronted bracket, breaks at a comma, then makes a free-standing claim about A. Direct ranking vs framed setup.
這座城市與五年前比，繁榮了許多 → 這座城市與五年前相比，繁榮了許多 (close the bracket with 相比, not bare 比)
五年前與這座城市相比，繁榮了許多 → 這座城市與五年前相比，繁榮了許多 (B is the fixed yardstick inside the bracket; A, the subject of the claim, comes first and after the comma)
這座城市與五年前相比繁榮了許多 → 這座城市與五年前相比，繁榮了許多 (a comma closes the frame before the claim)
English fronts 'compared with B' and runs straight into the clause. Chinese wraps the reference between 與 and 相比, then breaks at a comma before the claim about A begins.