一玩具车以4m/s的速度向右运动了3s后遇到一障碍物,花了2s在原地掉头,然后沿

题型:填空题

问题:

一玩具车以4m/s的速度向右运动了3s后遇到一障碍物,花了2s在原地掉头,然后沿原路匀速向左返回,再过4s后恰回到原出发点.以向右为正方向,试画出玩具小车在这段时间内的s-t图和v-t图.

考点:匀变速直线运动
题型:填空题

阅读理解。

     I am a Chinese boy. My name is Li Lei. I am twelve. My sister's name is Li Mei. She's

fourteen.'Li Mei and I are students. We like school.

     My mother is a teacher. She teaches English. My father is a policeman (警察). My young

brother's name is Li Hong. He is only four. We all like him.

1. Li Lei is _______.

A. Chinese

B. English .

C. American

2. Li Lei's sister is _______.

A. four

B. twelve

C. fourteen

3. Li Lei's mother and father are_______.

A. student and teacher

B. teacher and policeman

C. all teacher

4._______ like school.

A. Li Mei and Li Lei

B. Li Mei and his mother

C. Li Lei and his father

5. How many brothers does Li Lei have?

A. Three.

B. Two.

C. One.

题型:填空题

如图中的曲线分别表示淀粉、脂肪和蛋白质在消化道中各部位(依次用A、B、C、D、E表示)被消化的程度.

(1)图中的哪一条曲线表示糖类的消化过程?

(2)脂肪和蛋白质分别在哪些部位开始被消化?

(3)米饭的主要成分是淀粉,淀粉不甜,米饭咀嚼后为何变甜?

题型:填空题

如图所示,将无色酚酞溶液滴入下列溶液中,都变红色的是(  )

A.食醋、石灰水

B.石灰水、盐酸

C.石灰水、氢氧化钠溶液

D.食醋、盐酸

题型:填空题

陈奕迅有一首用数字命名的歌曲这首歌是什么?

题型:填空题

面爆破中,封泥长度不得小于()米

A、0、5米

B、0、3米

C、0、1米

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