连词成句，注意大小写及标点符号. 1.we must not cross street until the traffic light turns green.2.The shoemaker worked hard，but he was very poor.3.Someone loses a wallet but I give it to the police.4.Reaky gets some fun for it's time.5.We must walk down the stairs quickly.写出下列词语的反义词left-rightboring-interesting
写英语句子时 and 和 but 等前面要不要加标点符号？是不是没有什么关系还是有特殊要求？
as表示原因时前面要加逗号吗 还有because but什么的标点符号怎么用
