To 语者, 

Common mistake - drop

Common mistake - discuss

Common mistake - difficult

Common mistake - difference/different

Common mistake - decrease

Common mistake - day

Common mistake - damage

Common mistake - contact

Common mistake - consider

Common mistake - concern/concerned/concerning

Common mistake - complain

Common mistake - compensate

Common mistake - compared with/to

Common mistake - common/ordinary

Common mistake - come

Common mistake - cloth/clothes

Common mistake - closed or close

Common mistake - change

Common mistake - cannot & capable

Common mistake - take care