Thesub-multipleprefix“micro”means（）. A: thousandth(10tothe-3rdpower) B: millionth(10tothe-6thpower) C: billionth(10tothe-9thpower) D: trillionth(10tothe-12thpower)

Listen to the words and find out the correct meanings in English. 1. A: A measure of weight that is equal to a thousandth of a kilogram. B: Something to be discarded after use. C: Reprocess used items to make them usable again. D: Something useless.