物体放置的位置、方式不同，而它的重心在物体内的位置是（）。
A.不变的
B.不固定的
C.随机而变
D.按一定规律变化的
参考答案：A
非洲的最高峰是（ ）
A．德拉肯斯山脉
B．肯尼亚山
C．乞力马扎罗山
D．阿尔卑斯山
对话排序。
A. Yeah. I wasn't very outgoing.
B. Hey, Steve! Over here! Don't you remember me?
C. No, you weren't. But you were always friendly.
D. That's right.
E. But you used to be very quiet, didn't you?
F. Oh, wow! You are Paula, aren't you?
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