⑴继续____ ⑵朝.....外看____ ⑶造一个句子____
⑷拼写____ ⑸今天周几?____ ⑹和____
⑺昨天____
They waited and waited for something _______ to happen.
如图,点A与点A′在x轴上,且关于y轴对称,过点A′垂直于x轴的直线与抛物线y2=2x交于两点B,C,点D为线段AB 上的动点,点E在线段AC上,满足 |CE||CA|=|AD||AB| .
灰兔和白兔杂交,F1全是灰兔,F1雌雄个体相互交配,F2中有灰兔、黑兔和白兔,比例为9∶3∶4,则 ( )