问题
选择题
小刚用低倍镜观察到小鱼尾鳍内的血管及血液在血管内的流动情况，如图所示，其中血流速度最慢的血管是（ ）
A．1
B．2
C．3
D．2和3
答案
答案：B
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小刚用低倍镜观察到小鱼尾鳍内的血管及血液在血管内的流动情况，如图所示，其中血流速度最慢的血管是（ ）
A．1
B．2
C．3
D．2和3
答案：B
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Jim: Hello! This is Jim. 1_______ Jane: Speaking. Jim: Hi, Jane! How are you? Jane: Fine, thanks. And you? Jim: I'm fine, too. 2_______ Jane: 3_______ Jim: Would you like to go fishing with me? Jane: 4_______ But I have something to do this afternoon. Jim: How about tomorrow afternoon? Jane: OK. 5_______ Jim: Goodbye. Jane: Bye. |