Grammar fix
run up
to allow a bill or debt to increase
To spend money or use services so that you owe a large amount, often without noticing how much it adds up.
phrasal verbB2common
Hear it in context
Notice where the phrase sounds natural.
He ran up a huge phone bill calling his friends overseas.
In my opinion, it's easy for students to run up debts if they don't keep track of their spending.
Fix the pattern
One small grammar move makes it sound right.
Not: She ran up of a big bill.
Say: She ran up a big bill.
'Run up' takes the object directly — no 'of'.
Which sounds natural?
Tap the one a native speaker would say.
'Run up' is the everyday verb for letting a bill grow; 'incur a debt' is formal/financial.
Build natural chunks
Words that usually travel with it.
run up + bill/debt
- a bill
- debts
- a tab
- charges