1.This is his baseball.（改为否定句）
This isn't his baseball.
2.Is that her pencil case?（做否定回答）
No,it isn't.
3.This is _ a_ _ring_ in English.（对划线部分提问）
What is this in English?
4.My computer is black.（改为一般疑问句）
Is your computer black?
5.I spell it“R-U-L-E-R”.（对划线部分提问）
What do you spell it?