问题
选择题
I was speaking to Ann on the phone when suddenly we were _____. [ ]
A. hung up
B. hung back
C. cut down
D. cut off
答案
答案：D
搜题请搜索小程序“爱下问搜题”
I was speaking to Ann on the phone when suddenly we were _____. [ ]
A. hung up
B. hung back
C. cut down
D. cut off
答案：D
C的粒子从正极板的小孔无初速的进入匀强电场，到达负极板．这个粒子到达负极板时的动能为多少焦耳？（不计重力）
