Hello，my name is Danny. I am a tall boy. I have a big face and two big eyes. I can read books and write English. I am a good student. I have a happy family. My father and mother are teachers. My father is 35 years old and my mother is 33 years old. My father is tall and thin. He can swim and dive. My mother isn't tall. But she's thin. She can draw nice pictures.

写出近义词。

清晰—____    抚摸—____    沉思—____   严肃—____

某位同学在学校历史时制作了下表。根据表格内容判断，他所探究的主题是（    ）

 为了将放置在水平地面上重为100N的物体提升一定高度，设置了图1所示的滑轮组装置．当用图乙所示随时间变化的竖直向下的拉力F拉绳时，物体的速度v和物体上升的高度h随时间变化的关系分别如图丙和丁所示．（不计绳重和绳与轮之间的摩擦）下列计算结果正确的是（　　）