They have no classes ________ Saturday and Sunday. A. in B. on C. at D:from
–Where is your father? – He _________ Australia and he_________ Sydney for two weeks.
– How long has Robot _________ ? – Since2004.
Great changes _________ in Nanjing since the1990s.
My mother _________ a history teacher.
–Have you finished your homework? – _________ . Just half of it. How about you?