（）被称为第二代基因工程。
A.细胞工程
B.蛋白质工程
C.人类基因组计划
D.基因治疗
参考答案：C
Peter said he ______ when he got there but we have never heard from him since then.
A．was writing
B．would write
C．had written
D．has been writing
粗放：集约：经营
A．单薄：强壮：力量
B．自然：拘束：表情
C．钻石：珠宝：奢侈
D．单调：重复：样式
