1.First, we need to work on the chalkboard before we can start the math.
work on 影響,對…起作用;繼續工作;從事于…;設法說服
The scientists are still working on inventing new methods of reaching outer space.
科學家們仍致力于發明到達外層空間的新方法 。
The doctor told him that this kind of medicine may work on him.
醫生對他說這種藥對他可能有效 。