The Math problem is too difficult , we really don’t know ________ to do it .
There’s smile on the teacher’s face. I think she’s ______ our work.
—I’m not sure ______ Bill will come or not. —No, he isn’t.
—I want to know ______ your son is. —He is ten years old.
She told me the sun ______ in the east.
Tom asked my friend ______.