at a low ebb的用法和样例：
- Morale among teachers is at a low ebb.
- With Taiwan's economy at a low ebb,doing anything to provoke China into taking punitive action could be economically,if not politically,suicidal for Chen.
- There was a serious slump in the 1930s.
- The economy of the country is at a low ebb.
- Painting was then at its lowest ebb.
- A rise in oil prices depressed the car market.