I bought this cap yesterday and it (cost) me 70 yuan中cost为什么没有时态变化?

This cap is ___ (I). I bought this cap yesterday and it (cost) me 70 yuan中cost为什么没有时态变化? can have I cap this连词成句 I,try,may,this,on,cap怎么组成英文句子 I,try,may,this,on,cap怎么组成英文句子 I bought you this book?对this book提问 this is a japanese cap.i am a boy （改为一般疑问句并作肯定句回答）i am a boy this is a japanese cap两句都要改 This is the book that I bought it yesterday.改错 this is the book which i bought yesterday This is the bike ___ I bought last week填空 This is _____ new dress I bought yesterday. i bought this pair of trousers two days（ ）. you/book/this/I/bought/.该怎么组合 i bought my friend this book 改为一般疑问句 book,i,you,bought,this连词成句 LOOK,MUm.I BOUGHT YOU THiS BOOKabout America.(是什麽意思) LOOK,MUm.I BOUGHT YOU THiS BOOK.(是什麽意思) This is a book.I bought it.改为宾语从句