一般的性能劣化大体分为性能降低型和（）两种形式。
参考答案：突发故障型
2. _______ of their ancestors who made their living by hunting, the grown-ups ______up as hunters and the children as different animals.
A．In honor; put
B．In memory; dressed
C．In honor; were dressed
D．In memory; wore
表达产物具有C蛋白功能的癌基因是
A．myc基因
B．src基因
C．sas基因
D．sis基因
E．myb基因
