若方程（a﹣3）x^|a|﹣2﹣7=0是一个一元一次方程，则a等于 ____

读课文《瀑布》，填上适当的标点符号。

      站在瀑布脚下仰望____好伟大呀____一座珍珠的屏____时时来一阵风____把它吹得如烟____如雾____如尘____

增加：在缺词处加一个漏字符号（∧），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：在错的词下划一横线，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）只允许修改10处，多者（从第11处起）不计分。

    Travelled abroad, you should follow the customs of the country where you are visiting. When you invited, it is good manners to refuse or accept an invitation, either by writing or by telephoning. If you go to the patty, it polite to arrive on time. It is good manners to shake hand with your host. You can take a present if you like, possible a bottle of wine，a box of chocolates and some flowers. However, it was not bad manners to take nothing. It is not polite to stay too late before the other guests have gone. Also, it is suggested to or telephone a day or two late to thank your host.

When he ___ the bus , the poor man realized he had left his bag on it.