单项选择题The head of the Australian government is the_____.

单项选择题In the idiom ' in good feather ', we change ' good ' into ' high, full ' without changing meaning. This change of constituent is known as_____

单项选择题Peterloo Massacre happened in the city of_____.

单项选择题The official residence of the_____is at number 10 Downing Street, London.

单项选择题The U. S. is known as a great melting pot because ______.