Jim left a(n) ______ for you saying that he would come back in two hours.
He thinks _____ history about Chinese is very important.
How many states _______ the United States? Fifty.
My mother is strict both _____ me and ____ her work.
------ Do you know where Li Ming is working _____? ------ Maybe in Guangzhou, I think.
You should keep working hard ____ you have passed the exam.