begin–beginning

　　beg-begging

　　dig-digging

　　dip-dipping

　　drop-dropping

　　forget-forgetting

　　get–getting

　　hit-hitting

　　mop-mopping

　　nod-nodding

　　pat-patting

　　put–putting

　　run-running

　　swim-swimming

　　sit–sitting

　　win-winning

　　regret-regretting

　　set-setting

　　stop-stopping

　　一共19个,差不多够用了吧.