In 1964-1966, major resource of natural gas were discovered in the British sector of ______.

单项选择题Which of the following ways of word-formation doesn't change the grammatical class of the stems

单项选择题The Franklin Roosevelt came into power in the period of ______.

单项选择题[m], from the manner of articulation, it is ______.

单项选择题Distinctive sound refers to ______.