几乎用完了，快用光了
to have nearly finished a supply of something
We're running low on milk - could you buy some more? 我们的牛奶快喝完了——你再去买一些来好吗？
The radio batteries are running low. 收音机的电池快用完了。
Several hospitals are running low on the vaccine.
Tests revealed that she was low on vitamin B12.
I should have checked the oil but I didn't realize it was getting low.
See also: low adverb (LEVEL)