电焊工在焊接时应防止哪些事故苗头？

书面表达。

     假如你是李华，昨天你和同学们一起去郊外远足，你惊奇地发现田里树木被大量砍伐，河水变脏，

很少看到鸟兽的踪迹。你希望人们爱护动植物，多植树，不要砍树。保持河水清洁，不要伤害鸟类、

兽类，不要挖掘和采摘花草。为此，请你编写一封l00词左右的信，开头已给出。

Dear Editor,

     Yesterday l went hiking for a field trip. I was very surprised to                                                            

短文填空

The most important drink is water. Not many people understand this but it is quite t  1 . People can l  2   for a long time without food, but they will die if two or three days w  3   water. In h  2   weather, many people do not drink e  5   water, because they don’t know how much water they n  6  . After t  7   exercise, people need more water.

The water in man’s body is m  8   more than other matters(物质). We’d better have enough water, or we may get i  9  . Water is n  10   to all the living things. There will be no l  11   if there is no water.

So we must save water and don’t w  12   water.

鸟类的尾脂腺、羽毛和角质鳞都是表皮衍生物。（）

PSC行动代码45表示（）

A、通知下一港

B、在下一港纠正可滞留缺陷

C、与船旗国政府商议

D、关于违反防污规定排放的调查