he isn't playing cards with his friend.
陳述句變否定句的方法：
句中有動詞be( am ,
is ,are ,was ,were),情態(tài)動詞（can / could ,may ,must ,will ,would 等）,助動詞（如完成時(shí)態(tài)中的HAS / HAD ）,變否定句時(shí)直接在這些詞后加NOT ；否則要加助動詞Do ,
Does （主語第三人稱單數(shù)）,
Did （一般過去時(shí)）,原來的動詞要還原；另外,句中有SOME 是一般改為ANY ,如果用AND 要改為OR（因?yàn)榉穸ň渲械牟⒘幸肙R）
加油!不明白再問!i’mplaying withthe baby 。playing withthe baby 對它提問What are you doing ?