They have been working on the perfection of the new model.
他们一直在努力完善新型号。
None of this would have been possible without their help.
如果没有他们的协助，这事没有一样能办成。
What books have been set for the English course?
英语课布置要用哪些书？
The plans have been under discussion for a year now.
这些计划至今已讨论一年了。
No new SARS cases have been reported in the region.
该区没有新增非典型肺炎病例。