"Lead (metal)" and "lead (dog's head)" are spelt in the same way, but pronounced differently. This kind of sense relation is called ______

单项选择题The most striking phonetic difference between American and British English is the pronunciation of ______ in words.

单项选择题Grammatical context refers to ______ in which a word is used.

单项选择题The best known Australian animal is ______.

单项选择题To err is human, to forgive, divine , A little learning is a dangerous thing are taken from the poems written by ______.

单项选择题The head of the British Government is the ______.