题目

用方框中所给单词的适当形式填空。 why hour useful finish he （1） — is he late for class?— I don't know. （2） John is not good at English. Can you help? （3） I think history is in our life. （4） After Sally her homework, shetakes a walk along the river. （5） We play football on the playground forthree . 答案：【1】Why 【1】him 【1】useful 【1】finishes 【1】hours体积为1米3水的质量为　　千克，全部变成冰后，冰的质量为　　千克，冰的体积为　　米3（冰的密度为0.9×103千克/米3）。