— _____ you at school last night?
— No, I _____ at home.
A:Was; was
B:Were; were
C:Were; was
D:Was; were
第三周期元素R,它的原子最外电子层达到稳定结构所所需的电子数少于次外层与最内层电子数之差,且等于最内层电子数的整数倍,关于R的叙述中正确的是( )
已知在正方形ABCD中,对角线AC与BD相交于点O,OE∥AB交BC于点E,若AD=8cm,则OE的长为( )
百分之零点一二写作____,二五折改写百分数是____,它含有____个1%