If you cut back something such as expenditure or cut back on it, you reduce it. [V P n (not pron)] [V P on n] [V P] [Also V n P]
They will be concerned to cut back expenditure on unnecessary items…
他们将会考虑削减不必要的开销。
The Government has cut back on defence spending…
政府已经削减了国防开支。
We have been cutting back a bit: we did have thirteen horses, but now it’s nine.
我们已经作了一些削减：原来我们是有13匹马，现在只有9匹。