用手将一重为5N的物体全部压入水中，物体排开的水重8N，此时物体受到的浮力为____ N，放手后物体将____ （“上浮”或“下沉”或“悬浮”）。待物体静止时所受的浮力为____ N，排开水的体积为____ m³。

如图所示，木块a放在粗糙水平桌面上，木块b放在木块a上面，在水平拉力F作用下一起向右做匀速直线运动，空气阻力不计，下列判断正确的是（  ）

   I am an English girl. My name is Mary. I’m twelve. My dad and mom are English teachers. I have a brother（哥哥）. His name is Tom and he is thirteen years old. We are in China now. We are in Beijing No. 4 Junior High School. Tom is in Class 4, Grade 7 and I am in Class 9, Grade 7. I have a dog. My dog looks strong. It has a big mouth and two big black ears. We have many(许多) Chinese friends here. They are good.