This`s a key,that`s a pen这名话错在哪?

This`s a key,that`s a pen这名话错在哪? This's a pen and that's a ruler. Look This is a pen and it's red .The ruler is yellow.The key It's cup —What's this?—This is a pen.—Spell the word"key".—k what's_?__a pen ?a 、this;this is b 、this;it's c 、 that;that' this’s a pen and that’s a ruler.哪里错了 A:that's your pen.___ is my pen B:Do you __ this is interest what's that?( )is a key.1、this 2、that 3、it This is a pen and that’s an eraser.可不可以写成This is a pen and t lt's a key what's this?A this is key B it's key 怎样改错啊 This is a key,that is a pen