What'is your fax number?中的表语是谁?

What'is your fax number?中的表语是谁? What’s your fax number?表语是什么? What is your mother what is your name? What is your brother? What () is your ruler what is your What is your choice? what is your what is your what is your name What is your aunt? what is your hobby what is your mother? what is your what is your favourite what your name is? what is your hobby?