动词-ing形式的构成1
直接加-ing例：go-goingask-askinglook-lookingeat-eatingclean-cleaningcamp-camping野营jump-jumpingwait-waiting2
以y结尾直接加-ing例：hurry-hurryingcarry-carryingstudy-studyingcry-cryingplay-playingstay-stayingworry-worrying3
以不发音字母e结尾的动词，先去e，再+-ing例：write-writingmake-makingtake-takinghave-havingcome-comingchase-chasingsee-seeing（特例）4
末尾只有一个辅音字母，双写这个字母，再+-ingcut-cuttingshop-shopping;swim-swimming;plan-planning;chat-chattingdrop-dropping;stop-stopping;hit-hitting打撞;prefer-preferring;trek-trekking长途跋涉babysit-babysitting;Youarekidding
双写shut-shutting关闭spit-spitting吐痰get-gettingsit-sittingput-puttingrun-runningbegin-beginning5
特例：die-dyinglie-lying躺tie-tying系，捆，扎6
既可以双写，也可以不双写travel-travel（l）ing；quarrel-quarrel（l）ing争吵
