短文改错。 下列短文每一行均有一处错误。请按下列要求改正。 1）此行多一词；用斜线（/）将其划掉，并在该行右边横线上写出这个词，也将其用（/）划掉； 2）此行缺一词；在缺词处加一个漏字符号（∧），在该行右边横线上写上该词； 3）此行错一词；在错词下划一横线，并在该行右边横线上写上改正的词。 Mr. Smith with his little Tom, were going to the zoo by bus. The bus was crowded.                        1. _________ Little Tom sat on his father knees (膝盖). When the                          2. _________ bus stopped, an old lady got on to the bus, and the                            3. _________ boy jumps down at once and said, 'Would you have                          4. _________ my seat, Granny?' 'Thank you. You're good boy!'                            5. _________ Everyone laughed.