| 1. | A difficult problem or two occupied his mind . 有一两个困难问题在他心里回旋。 |
| 2. | How to improve the quality of products was a difficult problem to him . 如何提高产品质量对他来说可是个难题。 |
| 3. | The presence of water containing hard particles presents a difficult problem for the sealing . 含有坚硬颗粒的水,给密封带来一个难题。 |
| 4. | How to satisfy this mass demand and at the same time maintain cultural standards is a difficult problem . 如何在满足这一广大需要的同时又能保持文化水准是个难题。 |
| 5. | Crime is a difficult problem in many cities 犯罪在许多城市都是令人头痛的问题。 |
| 6. | User and group management is a difficult problem 用户和组管理是一个困难的问题。 |
| 7. | She was faced with a difficult problem / decision 她面临一个困难的问题/选择。 |
| 8. | Fish disease has been a difficult problem faced by fish farmers 鱼病是养鱼户经常面对的难题。 |
| 9. | Fish disease has been a difficult problem encountered by fish farmers 鱼病是养鱼户面对的难题。 |
| 10. | This is a difficult problem . at the same time it is very interesting 这是个困难的问题,但却极为有趣。 |