They're in the classroom doing thier homework.为什么要用doing ,能否用do?如题

Lucy and Lily are sisters .They're twiins .They're in the same class .Lucy studies bett We aren't in different ----------.They're in ------------- class. .填写单词.Justin and michael come from the USA,but they'rebut they're in C---1---- now.They're n--2--- students in Li Ming's class.They're c--3---.They're often in the same c--4--.And Li Ming t--5-- they look the same.1------- 2------ 3------ 4-- 完形填空Jim,Mike,Dick and John are good friends．They're in the 26 class．Jim,Mike,Dick and John are good friends．They're in the 1 class．They like to play football when they're 2 ．Sometimes they play football after lunch．Then they hurry they're in the dining-room. The best things in life.they're look there theyre in the they are in the same class They have four (class) in the morning. Are they in the same class We're in the same class.（改为一般疑问句：_____ ______ in the same class?） ( )are they ( )in the kitchen?they're cooking. 【急求】根据短文内容及首字母提示,填写所缺单词,使句子意思完整.（见补充）Justin and Michael come from the U.S.A.,but they're in C_________ now.They're n________ students in Kangkang's class.They're c________.They're of They're living in the same a .they're good friends How is everyone in your class going?怎么回答?they're fine还是well? 对划线部分提问 They're in Class Three.(Three)用括号里的词提问 How ( )they are listening to the the teacher in class They --------never late for the--------(one) class in the morning