请问tiptoe , scurries , lick的 过去式是什么?

请问tiptoe , scurries , lick的 过去式是什么? tiptoe into the 大象用脚尖走路?Elephants walk on tiptoe 这句话中,tiptoe为什么没有s?大象有不使用一个脚趾走路,况且是elephants.可是教科书上是这么写的,这里有什么知识点吗?那请问是什么词性的呢？ 1.（狗）朝他们叫______________2.Elephants walk on tiptoe.(对on tiptoe提问）________ _________ elephants walk? 如elephants walk on tiptoe或fish sleep with their eyes open之类的英语 in order not to be noticed , he walked into the room on tiptoe only -------(fall)down onto the floo怎么填啊 什么叫 为了不被注意他摔在了地上?. 英语问题（50分,回答好追加）1 This is the place where we played.这里的where为什么能换成to which?2 I left the U.S for China.这句话是不是我离开了美国来到了中国?3 on tiptoe是踮着脚,是不是可以这样说：“H 写一篇英语作文,80字左右 根据下列提示写一篇作文：the biggest living animals on land,eat 100--1000pounds of grass in a day,live 60--70years,no bones in the back of elephants' feet--only fat,walk on tiptoe,move quietly,grow large t 读短文内容,判断句子正（T）误(F)In our world,there are many amazing things.When fish sleep,they keep their eyes open.Elephants are the biggest on land,but they walk on tiptoe.Snakes don't have ears,but how can they hear They hear with Most children are interested in amazing things , and they wonder______. A. when can they see UFOs. B. how can elephants walk on tiptoe. C. why do fish sleep with their eyes open. D. why there is no plant life without lightning. 请问? 请问, 请问： 请问 请问： 请问, 请问: 请问：