已知关于x的一元二次方程(k+4)x2+3x+k2+3k-4=0的根为0，则k等于[ ]
A. 1
B. -1
C. 4
D. -4
答案：A
生殖器官发育最显著的时期是
A．新生儿期B．幼年期C．青春期D．生育期E．更年期
The _____________ we do our homework, the __________ mistakes we will make
A．more careful, less
B．more carefully, less
C．more carefully, fewer
D．more careful, fewer
