以下为原句基础上,改正后的内容：It is seven pm now,her family are doing different things.Kate's father is reading a book.Mother is watching TV,(and) she looks very happy.Kate's grandfather,Henry,is listening to the radio.Mrs.Henry is cleaning the room.Kate is doing her homework.Kate's sister,Betty,is playing computer games.
标注：1.第一句,不算错,不过按习惯把now 放后面
2.family 表示整个家庭时谓语用第三人称单数,表示各个家人时,用复数.根据语境,应该是指家人,所以用are
3.讲到祖父和祖母时,根据语境时间,应该是现在正在发生的,谓语应该是正在进行时,而不是过去进行时,所以要把was 都改成 is,上下文一致.
4.最后一句,也是正在进行时,应该是 is doing sth,而is to do ,表示将要做.