一年级有三个班，各班的人数如下表：

根据短文内容，选择最佳答案。
B
    Hello! My name is Kate. This is my bag. It's a nice bag, right? It is from my mother.
    What's in my bag? A ruler is in it. And the ruler is white. It's not mine. It's Lily's. Lily is my sister. She likes white but I don't. Two pencils are in it, too. One is red and the other is blue. They are mine. Look, a nice watch is in it. The watch is white and blue. It's mine and it's from my father. A notebook is in my bag, too. The notebook is yellow and blue. Is this notebook mine? No, it's Anna's. Anna is my cousin. She likes yellow and blue very much.

在正方体ABCD﹣A₁B₁C₁D₁中，M为棱A₁B₁的中点，则异面直线AM与B₁C所成的角的大小为　____ （结果用反三角函数值表示）．

有下列仪器，在实验中使用仪器的说法错误的是

肝脏分泌的胆汁和和胰腺分泌的胰液要通过导管流入十二指肠．（判断对错）