问题
选择题
I didn't pass the math exam last month. _____, how do you study for a math test? [ ]
A. By accident
B. By mistake
C. By the way
D. By the time
答案
答案：C
搜题请搜索小程序“爱下问搜题”
I didn't pass the math exam last month. _____, how do you study for a math test? [ ]
A. By accident
B. By mistake
C. By the way
D. By the time
答案：C
=(2t-1)i-2tj+costk，k≠0当A=0时，A=2i+j，则A等于（）。
sintk