比不上grammar point · tier 1 · negative potential comparison 比不上 (A cannot match up to B; A falls short of B)
· bǐ bu shàng
Negative comparison: A cannot measure up to B; B is the better one, A the lesser. Built as a potential complement — 比 (match) cannot reach 上 (level with).
Two things, and the first one tries and fails to match the second.
序 · The move
1Put the lesser thing first — that is A, the one that cannot pull level.Is A really the weaker one? Swapping A and B reverses who falls short; 比不上 means B is better.
2After 比不上 set the standard A fails to reach — that is B, the better one.B is the higher mark, not the loser.
3If you name a shared quality, hang it at the end (有價值); left bare, 比不上 already means 'falls short of'.No second 比, and no 很 — 比不上 is one welded unit carrying its own comparison.
例 · Examples
1買來的玩具the toy that was bought (A, the lesser)雖然although精緻finely made，但yet比不上cannot measure up to / falls short of親自做的the one made by one's own hand (B, the standard)有價值valuable (the shared quality)。
The bought toy is finely made, yet it cannot measure up to a handmade one in worth.
界 · Boundary
A比B (X)
A比B ranks A above B (A is more); A比不上B ranks A below B (A cannot reach B). The bare 比 fronts the winner; 比不上 fronts the one that falls short.
不如 flatly states A is not as good (no verb of trying); 比不上 frames the same shortfall as a failed reach — A tries to match B and cannot get level. Near-identical in use; 比不上 is the potential-complement telling.
A沒有B（那麼）X
沒有 needs a quality named to negate (A is not as X as B); 比不上 can stand bare on the whole standing (A cannot match B), with the quality optional at the end.
親自做的比不上買來的玩具 when you mean the bought one is worse → 買來的玩具比不上親自做的 (the one that falls short goes first)
A比比不上B → A比不上B (比不上 is one unit; no extra 比)
A比不上B很有價值 → A比不上B有價值 (drop 很; 比不上 already means falls short)
English 'A can't match B' or 'A is no match for B' keeps the quality up front and the standard last; Chinese fronts the loser A, welds 比不上 as one block, and ends on the standard B with the quality optional and bare.