一个小小的语法疑惑When did you begin feeling ill?这个feel为什么要加ing啊!直接用feel原形不可以吗?

一个小小的语法疑惑When did you begin feeling ill?这个feel为什么要加ing啊!直接用feel原形不可以吗? 微积分 导数 小小的疑惑 50%的概率的东西如出现25个小再出现一个大再出25个小的概率是多少?小小小小小小小小小小小小小小小小小小小小小小小小小大小小小小小小小小小小小小小小小小小小小小小小小小小 就是 一个微分方程的疑惑 一个小小的SAT语法问题.25years 后面的谓语动词应该是单数还是复数? 一个小小的计算…小小小小的 一个小小的选择题 一个小小的应用题 一个小小的计算 when 后面直接+doing 或者+ did 是什么语法现象? when 后面直接+doing 或者+ did 是什么语法现象? “never for asecond”Tim says “did I doubt that yo“never for asecond”Tim says “did I doubt that you would come to help me when I was in trouble”的中文翻译 What did Mary ask yo u just now She asked me ( )What did Mary ask yo u just now She asked me ( )1 whom john wanted t o see 2 whom didi john want t o see 3 john wanted to see whm 4 john wanted whom tosee 此题选1 为什么呢 这个题的语法是 What did you see (her doing) when you got there?括号里填her doing的语法是什么啊? 英语语法很低级的一个问题?Do的过去时是Did Dose的过去时是什么?如：When did you.可以说When did she. 一棵花也算一个小小的生态系统? 最近在学习有理数,有点小小的疑惑——百分数是属于有理数吗? yo-yo的复数是什么