2.加入,参与释义下的同义词 uniting joining adding on appending tacking attaching combining annexing

3.增长,扩展释义下的同义词 extension enlargement expansion accession continuation prolongation accretion addendum increment augmentation increase

4.总共,计算释义下的同义词 counting enumerating adding computation calculation totalling up summation tallying reckoning

5.附加,辅助,补充释义下的同义词 tailpiece codicil interpolation appendage add annexation addendum suffix on additament superaddition supplement insertion attach