The neighbours often visit the old man, so he doesn’t feel at all.
A:friendly
B:alone
C:lonely
D:lively
It will be____on Sunday. I'm going to____.
用正确的化学符号填空:
在平面直角坐标系xOy中,以原点O为圆心的圆过点A(13,0),直线y=kx﹣3k+4与⊙O交于B、C两点,则弦BC的长的最小值为____.