Dear John,

    How are you? Nice1 you. From your letter I know a lot about you and your school. Now let me2 something about me and my school.

    I am thirteen years old. I am 3 Class Two, Grade One. My father is a teacher. He is my 4English teacher. My mother is a doctor. I have a sister.5 are in the same school. We can sing(唱) many songs6 English.

    This is my classroom.7have a class photo on the wall. But can you see 8photo? It's at the door. In the classroom 9 our desks and chairs. Mrs. Green is our head teacher.10 is very kind(友好).

    Please come and have a look at our school if you are free.

Millie

如图（a）所示，一个质量为1千克、底面积为3×10^﹣2米²的薄壁圆柱形容器放在水平地面上，且容器内盛有4×10^﹣3米³的水。

图4是昆明准静止锋示意图。从图可知（   ）