heavy schoolbags have long been a serious problem for them这句话中的long 是什么用法

heavy schoolbags have long been a serious problem for them这句话中的long 是什么用法 E-schoolbags.Is your schoolbag too heavy The e-schoolbag will help you .It is said that e-scho Is your schoolbag too heavy?The e-schoolbag will help you.It is said that e-schoolbags are going to be brought into (16) ______in Chinese middle schools soon.Heavy schoolbags have been a serious (17) _____ for a long time,but the e-schoolbags will (1 Heavy schoolbags are causing back problems.It sure is.But we can't decide what to do/how to do it答案是what to do,但是第二个为什么不对,希望给出具体清楚的解释, Is your schoolbag too heavy to carry?The eIs your schoolbag too heavy to carry?The e-schoolbag will help you.It is says that e-schoolbag will come into use in Chinese middle schools soon. Heavy schoolbags have been a serious problem for a long ti We've got our schoolbags. What,s in your schoolbags? 我是接刚刚那个问题的分不多了高手速来Is your schoolbag too heavy The e-schoolbag will help you .It is said that e-schoolbags are going to be brought into ( 1 )in Chinese middle school soon.Heavy schoolbag have been a serious ( 2 ) fo hav a great where are the twins'schoolbags什么意思 Some are smaller than our schoolbags是什么意思 英语一篇短小阅读.急要~Is your schoolbag too heavy to carry?The e-schoolbag will help you.It is said that e-schoolbags are going to be brought into use in Chinese middle schools soon.In fact,the e-schoolbag should perhaps be called an e-text 初一上册英语题（明天就要交了帮下）用所给词的正确形式填空（1）Be＿（care）.The road is very.(2)It snowed very＿(heavy).(3)So you told the monkey＿(not bring)me anything.句型转换(每空一词)(1)People usually hav where are their schoolbags?()are in the classroom 填什么 Do you like small schoolbags or big ones的意思 (---)are these schoolbags?They're green ,yellow ,blueand red. We've got our schoolbags.怎么改为一般疑问句 Heavy look和heavy tongue,heavy