Look!There are many beautiful kites in the sky.they're in different _____是填size还是sizes?

Look!There are many beautiful kites in the sky.they're in different _____是填size还是sizes?
Look!There are many beautiful kites in the sky.they're in different _____
是填size还是sizes?

Look!There are many beautiful kites in the sky.they're in different _____是填size还是sizes?
应该填sizes~
前面都用they're了,又是in different,而且size也是可数名词,明显是填复数形式.

size，因为加了s就是表示尺寸了。没加就是表示大小。这句话的意思是看到很多风筝在天空飞，都各有大小，各不相同、

sizes