阅读下面短文，根据语境、音标或所给单词的提示，在每个空格内填入一个恰当的词，要求所填的词意义准确、形式正确，使短文意思完整、行文连贯。

    Every year many people get  or lose their lives in traffic accidents. How can we keep swhen we walking on the street. First, we must obey the traffic  (rule). We can cross the street only when we see the green "walk"  [sain]. Second, b we cross the street, we must stop and look  ways - look left, look  and look left again.  [θɜ:d], we must never play on the street. Last,  （it）good to help kids and old people cross the street. All of us should  very careful when we are walking on the street.