新概念英语 不能说my this a pen?要说 my pen?为什么?

新概念英语 不能说my this a pen?要说 my pen?为什么? 我的这一支钢笔 不能说my this a pen?要说 my pen? this is a my pen my pen 英语作文 This is my a pen?对还是This is a my pen?对 是This is my blue pen 还是This is my a blue pen This is my pen f_____Emma. what's this?It's a pen.为什么不能说是"this is a pen.我们老师说就是不能说this There is a pen in my pen. It is _____. A.pen B.my a pen C.a my pen D.my pen my pen This is my pen中就my pen提问