A:DNA模板和能量
B:逆转录酶
C:解旋酶、DNA聚合酶等酶
D:脱氧核苷酸
He held a glass with care because he was afraid of ____ (break) it.
以下选取的是八年级同学小江学习生活的三个镜头,阅读后回答问题。
已知函数y=(k+2)xk2+k-4是关于x的二次函数,则k=____ .