480÷80=____ 140÷70=____ 320÷40=____ 180÷60=____
观察洋葱表皮细胞时视野中出现如图所示的现象,则最可能出错的步骤是( )
— When did the story happen?
— Last month.
When was _______ umbrella_______?
— ______. To tell the truth, I've seen it twice.