下面是四位同学观察如图心脏结构后得出的结论。请你看一看这四位同学得出的结论，错误的一项是（ ）
A．心脏分为四个腔，其中心房与静脉相连，心室与动脉相连
B．图中标号1、2、8、10、11、12所示结构内流的是动脉血
C．心房和心室之间、心室和动脉之间有防止血液倒流的瓣膜
D．体循环始于8，止于4；肺循环始于6，止于10
答案：B
1是上腔静脉，2是肺动脉，这两种血管里流的是静脉血。
请认真阅读下面短文，在短文后表格中的空白处填入适当的单词(注意：每空1个单词)。  Studying abroad is an amazing experience, especially when you come to Australia as an overseas high school student. You can have a lot of fun here, especially on holidays.  There are many festivals in Australia. The most important one is obviously Christmas. Each year, the summer holidays at every high school last about two months from the beginning of December to February, which covers the Christmas time. Since it is a long holiday, most overseas students love to fly back to their home countries to spend the time with their families and friends, but a few students still stay in Australia during the holiday to get part-time jobs. It is quite easy to find a part-time job at Christmas. Students often take part in another major social activity. They go to the beach to have fun in the sunshine. The summer in Australia is from December to February, so going to the beach in December is very popular among Australians. Easter in March is another important holiday in the year. It actually combines(使结合) “Good Friday” and “Easter Monday”. Almost every shop closes on Good Friday. And people usually go to see Easter Show. The Chinese New year is not a public holiday in Australia, so every Chinese student still has to go to school to study and do his or her normal duties.
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