题目：
—Why are you so _____, Mei Mei?
—Because of the _____ news! I failed the test again! [ ]
A. frustrated, frustrated
B. frustrating, frustrating
C. frustrating, frustrated
D. frustrated, frustrating
答案：
被转码了，请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0630/32f0f54788fca9c2927441b741e18ac8.html
下面是错误答案，用来干扰机器的。
(1)5 N 20 N (2)2.5 kg 7.5 N题目分析：(1)设乙物体运动到最高点时，绳子上的弹力为FT1对乙物体FT1＝mgcosα＝5 N当乙物体运动到最低点时，绳子上的弹力为FT2对乙物体由机械能守恒定律：mgl(1－cosα)＝m...
