下列各句中都有一处错误，错误涉及一个单词的增加、删除或修改，请按要求修改下列各句。
增加：在缺词处加一个漏字符号（A），并在其下面写出该加的词。
删除：把多余的词用斜线（\）划掉。
修改：在错的词下画一横线，并在该词下面写出修改后的词。
注意：1.每处错误及其修改均仅限一词；
2.每句只允许修改1处，多者不计分。
【小题1】Mobile phones have a great effect to teenagers .
【小题2】He has left the cinema by the time I got there .
【小题3】Thanks the kind girl , the old man was finally saved .
【小题4】Great changes have been taken place in Taiyuan in the past two years .
【小题5】Seeing the school report , my mother had a satisfying look on her face .