is-- am-- are-- do-- go-- underpay--
问题描述：
is-- am-- are-- do-- go-- underpay--
become-- die-- have-- wear-- leave--
meet-- can-- teach-- take-- swim--
ride-- say-- see-- hold--
答
is-- was am--was are-- were do--did go-- went underpay--underpaid
become-- became die-- died have--had wear-- wore leave--left
meet--met can--could teach-- taught take--took swim--swam
ride-- rode say-- said see--saw hold--held