胎儿体内无()血,均是()血;进入()的血液含氧量高且营养丰富,而注入()的血液含氧量及营养少。
参考答案:纯动脉;动静脉混合;肝、心、头部及上肢;肺及身体下部
根据对话内容,从方框中选择5个恰当的句子完成对话,并将所选句子前的字母代号写在答题卡上的相应题号后.
A:We have to meet the others at 8:30 at the reserve(自然保护区),don’t we?
B: 1
A:Do you know how to get there?
B:2 It will take us about two hours to get there by bus.
A:3
B:It’s an area that protects lots of different animals.
A:4
B: I’m not really sure.I know there are many different kinds of birds there and I’m going to take my camera with me.
A:5 What clothes are you going to wear?
B:Well,if it’s wet,I will wear my strong shoes and take my raincoat with me.
A:So will I.
采煤工作面人员进入机道作业前应做好哪些工作?